This invention relates to novel processes for producing 4-substituted benzopyran derivatives useful as medicines, agrichemicals and cosmetics, as well as intermediates for their synthesis and processes for producing such intermediates.
One of the prior art techniques known in the field contemplated by the invention is a process for synthesizing 4-substituted benzopyran derivatives via 4-bromobenzopyran drivatives (JPA Hei 7-188210).
According to JPA Hei 7-188210, a compound represented by the general formula (XVIII) (the chemical formulae embraced by the general formula (XVIII) are set forth in the List of Chemical Formulae at the end of the specification; all the chemical formulae referred to hereinafter are collectively set forth in the List of Chemical Formulae at the end of the specification) is reacted with carbon monoxide and amine in the presence of a palladium catalyst to give an amide form represented by the general formula (XXVI).
A method generally known to be applicable in the synthesis of benzopyrans is by subjecting a compound of the general formula (D) to thermal cyclization reaction to give a compound of the general formula (E) (see, for example, Australian Journal Chemistry, 1971, Vol. 24, pp. 2347-2354).
It is also known that the 4-bromobenzopyran derivative (XVIII) can be produced from a compound of the general formula (XII) in six steps (JPA Hei 5-294954). According to JPA Hei 5-294954, an acetophenone derivative represented by the general formula (XII) (where Z5 and Z6 which may be the same or different represent a hydrogen atom, a lower alkyl group, a lower haloalkyl group, a halogen atom, a lower haloalkoxy group, an amino group, an acylamino group, a nitro group, a cyano group, an alkoxycarbonyl group, an optionally substituted lower alkylsulfonyl group or an arylsulfonyl group or, when taken together, represent a substituent xe2x95x90Nxe2x80x94Oxe2x80x94Nxe2x95x90) is condensed with an acetone derivative represented by the general formula (XIII) (where Z7 and Z8 which may be the same or different represent a hydrogen atom, a lower alkyl group or a substituted lower alkyl group or, when taken together, represent a polymethylene group or a substituent forming a heterocycle) in the presence of a base such as pyrrolidine to give a benzopyran derivative represented by the general formula (XIV) (where Z5, Z6, Z7 and Z8 have the same meanings as defined above). The benzopyran derivative (XIV) is reduced with a suitable reducing agent such as sodium borohydride to give a benzopyran derivative represented by the general formula (XV) (where Z5, Z6, Z7 and Z8 have the same meanings as defined above). The benzopyran derivative (XV) is dehydrated with a suitable dehydrating agent such as p-toluenesulfonic acid to give a benzopyran derivative represented by the general formula (XVI) (where Z5, Z6, Z7 and Z8 have the same meanings as defined above). The benzopyran derivative (XVI) is brominated with a suitable brominating agent such as bromine to give a 3,4-dibromobenzopyran derivative represented by the general formula (XVII) (where Z5, Z6, Z7 and Z8 have the same meanings as defined above). The 3,4-dibromobenzopyran derivative (XVII) is treated with a suitable base such as sodium hydroxide to give a 4-bromobenzopyran derivative represented by the general formula (XVIII) (where Z5, Z6, Z7 and Z8 have the same meanings as defined above).
Other processes for producing the benzopyran derivative (XVI) as an intermediate for the general formula (XXVII) have been reported elsewhere (Tetrahedron Letters, 1993, 34, 1815-1818; The 20th Symposium on Progress in Organic Reactions and Syntheses, Shizuoka (1994)).
According to Tetrahedron Letters, 1993, 34, 1815-1818, a compound (IIf) and trimethylsilyl acetylene are subjected to cross-coupling reaction in the presence of copper(I) iodide and tetrakis(triphenylphosphine)palladium and the resulting trimethylsilyl acetylene compound is treated with potassium carbonate in methanol to give a compound represented by the formula (XIX) set forth below. This compound is reacted with hexafluoroacetone using n-butyllithium to give a compound represented by the formula (XX). This compound is reduced with a palladium-barium sulfate catalyst under a hydrogen atmosphere to give a compound represented by the formula (XXI). This compound is reacted with sodium hydride to give a benzopyran derivative represented by the formula (XXII).
According to the 20th Symposium on Progress in Organic Reactions and Syntheses, Shizuoka (1994), 4-fluoronitrobenzene and acetylene represented by the general formula (XXIII) (where Z9 represents a methyl group or a fluoromethyl group) are reacted in the presence of sodium hydride to give a compound represented by the general formula (XXIV) (where Z9 has the same meaning as defined above). This compound is heated in dichlorobenzene to give a benzopyran derivative represented by the general formula (XXV) (where Z9 has the same meaning as defined above).
In the production method of the invention, phenylpropargyl ethers are one of the important intermediates for synthesis and can be produced by known methods such as those described in Synthetic Communications, 19, 1255-1259 (1989) and U.S. Pat. No. 5,463,059.
According to Synthetic Communications, 19, 1255 (1989), a phenol represented by the general formula (H) and a substituted propargyl alcohol represented by the general formula (J) are condensed in benzene in the presence of diethyl azodicarboxylate and triphenylphosphine to give a compound represented by the general formula (K).
According to U.S. Pat. No. 5,463,059, a compound represented by the general formula (L) and a substituted propargyl alcohol represented by the general formula (M) (where L represents a leaving group such as a halogen atom, a trifluoroacetoxy group or an alkoxycarbonyloxy group) are reacted in acetonitrile in the presence of an organic base and a catalytic amount of a copper salt to give a compound represented by the general formula (N).
Other prior art techniques known in the field contemplated by the invention are processes for synthesizing 4-substituted benzopyran derivatives via 4-bromobenzopyran derivatives (XVIII) (JPA Hei 7-17965, JPA Hei 7-188210 and Tetrahedron Letters, 1995, 36, 87-90). According to JPA Hei 7-17965 and JPA Hei 7-188210, the general formula (P) (where Za and Zb which may be the same or different represent a hydrogen atom, a lower alkyl group, a lower haloalkyl group, a halogen atom, a lower haloalkoxy group, an amino group, an acylamino group, a nitro group, a cyano group, an ester group, a lower alkylsulfonyl group or a lower arylsulfonyl group or, when taken together, represent a substituent xe2x95x90Nxe2x80x94Oxe2x80x94Nxe2x95x90; Zc and Zd which may be the same or different represent a hydrogen atom, a lower alkyl group or a substituted alkyl group or, when taken together, represent a polymethylene group or a substituent forming a heterocycle) is reacted with carbon monoxide and amine in the presence of a palladium catalyst to give an amide form represented by the general formula (Q).
However, the reaction for the synthesis of benzopyran having a bromine-containing group introduced at 4-position involves so many steps that cumbersome treatment procedures are required. In particular, the intermediate benzopyran derivative (XIV) is a labile compound, so large amounts of decomposition products occur as by-products during the synthesis of the benzopyran and very cumbersome post-treatment procedures are involved. As a further problem, due to their labile nature, derivatives having acid- or base-sensitive functional groups such as a perfluoroalkyl group in Z7 and Z8 cannot be synthesized without suitable protective groups. Because of these problems, extreme difficulties have often been encountered in the synthesis of the benzopyran. In order to produce the compound (XXIV), the presence of a nitro group in para-position is essential, so the process involving the formation of this compound as an intermediate does not have extensive applicability.
The method of synthesis of 4-halobenzopyrans that is described in JPA Hei 5-294954 has a long synthesis pathway and is not satisfactory in terms of yield. It has therefore been desired to develop a synthesis pathway that is short and yet has a broad range of applications. The idea of condensing phenol and alcohol using the Mitsunobu Reaction as described in Synthetic Communications, 19, 1255-1259 (1989) turned out to be very inefficient (low yield) when it was applied to the synthesis of the compounds of the present invention. U.S. Pat. No. 5,463,059 gives no example of condensation between a dihalomethyl-substituted propargyl alcohol and phenol and it involves other difficulties such as the use of expensive anhydrous trifluoroacetic acid and 1,8-diazabicyclo(5.4.0)-7-undecene.
Under these circumstances, it has been required to develop a process for producing 4-substituted benzopyran derivatives that involves a smaller number of steps, that is economical and which yet allows for easy post-treatment and purification procedures.
As a result of their intensive studies, the present inventors found very useful processes for producing 4-substituted benzopyran derivatives that were shorter, safe, high in yield and which yet allowed for easy treatment and purification procedures.
The present invention provides the following various production processes.
1. A process for producing 4-substituted benzopyran derivatives represented by the general formula (G-VI) [where R1 and R2 which may be the same or different represent a hydrogen atom, an optionally substituted lower alkyl group, an optionally substituted lower alkoxy group, an optionally substituted lower alkoxycarbonyl group, an optionally substituted lower alkylsulfonyl group, an optionally substituted arylsulfonyl group, a halogen atom, a nitro group, a cyano group or NYaYb (where Ya and Yb which may be the same or different each represent a hydrogen atom, an optionally substituted lower alkyl group, an optionally substituted lower alkoxycarbonyl group, an acyl group, an optionally substituted lower alkylsulfonyl group or an optionally substituted arylsulfonyl group or, when taken together with the nitrogen atom to which they are bound, may form a 3- to 8-membered ring) or, when taken together, represent a substituent xe2x95x90Nxe2x80x94Oxe2x80x94Nxe2x95x90; R3 and R4 which may be the same or different represent a hydrogen atom or an optionally substituted lower alkyl group or, when taken together with the carbon atom to which they are bound, represent a polymethylene group or a substituent forming a heterocycle, provided that R3 and R4 are not both a hydrogen atom; R5 and R6 which may be the same or different represent a hydrogen atom or an optionally substituted lower alkyl group] by any one of the schemes (1), (2), (3), (4), (5) and (6) containing a plurality of steps as indicated below, namely,
(1): (1-1)xe2x86x92(1-2)xe2x86x92(1-3)xe2x86x92(1-4)xe2x86x92(1-5);
(2): (2-1)xe2x86x92(2-2)xe2x86x92(2-3)xe2x86x92(2-4)xe2x86x92(2-5)xe2x86x92(1-5);
(3): (3-1)xe2x86x92(3-2);
(4): (4-1)xe2x86x92(4-2);
(5): (a-1)xe2x86x92(a-2)xe2x86x92(b-1)xe2x86x92(b-2)xe2x86x92(1-5); and
(6): (a-1)xe2x86x92(a-2)xe2x86x92(d-1)xe2x86x92(d-2)xe2x86x92(d-3);
(1-1) the step of reacting a compound of the general formula (II) (where X and Y which may be the same or different represent a leaving group such as a halogen atom, an optionally substituted lower alkylsulfonyloxy group or an arylsulfonyloxy group; R1 and R2 have the same meanings as defined above) with an olefin of the general formula (III) (where R3 and R4 have the same meanings as defined above) to give a compound of the general formula (IV) (where Y, R1, R2, R3 and R4 have the same meanings as defined above);
(1-2) the step of reacting the resulting compound of the general formula (IV) with a halogenating agent to give a compound of the general formula (V) (where Y, R1, R2, R3, R4 and Hal have the same meanings as defined above);
(1-3) the step of reacting the resulting compound of the general formula (V) with a base to give a compound of the general formula (VI) (where Y, R1, R2, R3, R4 and Hal have the same meanings as defined above);
(1-4) the step of reacting the resulting compound-of the general formula (VI) with a base to give a 4-halobenzopyran of the general formula (I) (where Y, R1, R2, R3, R4 and Hal have the same meanings as defined above);
(1-5) the step of reacting the compound of the general formula (I) with carbon monoxide and a compound of the general formula (G-III)
R5R6NHxe2x80x83xe2x80x83(G-III)
xe2x80x83(where R5 and R6 which may be the same or different represent a hydrogen atom or an optionally substituted lower alkyl group) in the presence of a metal to give a 4-substituted benzopyran derivative of the general formula (G-VI) set forth above;
(2-1) the step of reacting a compound of the general formula (III) with acetylene of the general formula (VII) (where R3 and R4 have the same meanings as defined above) to give a compound of the general formula (VIII) (where Y, R1, R2, R3 and R4 have the same meanings as defined above);
(2-2) the step of reacting the resulting compound of the general formula (VIII) with a reducing agent to give a compound of the general formula (IX) (where Y, R1, R21 R3 and R4 have the same meanings as defined above);
(2-3) the step of reacting the resulting compound of the general formula (IX) with a base to give a benzopyran derivative of the general formula (X) (where R1, R2, R3 and R4 have the same meanings as defined above);
(2-4) the step of reacting the resulting compound of the general formula (X) with a halogenating agent to give a 3,4-dihalobenzopyran derivative of the general formula (XI) (where R1, R2, R3, R4 and Hal have the same meanings as defined above);
(2-5) the step of reacting the resulting compound of the general formula (XI) with a base to give a 4-halobenzopyran derivative of the general formula (I) (where R1, R2, R3, R4 and Hal have the same meanings as defined above);
(3-1) the step of reacting a compound of the general formula (G-I) (where R1, R2, R3 and R4 have the same meanings as defined above) with carbon dioxide in the presence of a base to give a compound of the general formula (G-II) (where R1, R2, R3 and R4 have the same meanings as defined above) or a salt thereof;
(3-2) the step of reacting the resulting compound of the general formula (G-II) or salt thereof with a compound of the genera formula (G-III)
R5R6NHxe2x80x83xe2x80x83(G-III)
xe2x80x83(where R5 and R6 which may be the same or different represent a hydrogen atom or an optionally substituted lower alkyl group) to give a 4-substituted benzopyran derivative of the general formula (G-VI) set forth above;
(4-1) the step of reacting a compound of the general formula (G-I) (where R1, R2, R3 and R4 have the same meanings as defined above) with a compound of the general formula (G-IVa) (where R5 and R6 which may be the same or different represent a hydrogen atom or an optionally substituted lower alkyl group) or a compound of the general formula (G-IVb)
R6aNCOxe2x80x83xe2x80x83(G-IVb)
xe2x80x83(where R6a represents an optionally substituted lower alkyl group) in the presence of a base to give a compound of the general formula (G-V) (where R1, R2, R3, R4, R5 and R6 have the same meanings as defined above);
(4-2) the step of subjecting the resulting compound of the general formula (G-V) to thermal cyclization reaction to give a 4-substituted benzoyran derivative of the general formula (G-VI) set forth above;
(a-1) the step of reacting an alcohol of the general formula (C-I) (where R3 and R4 have the same meanings as defined above) with a compound of the general formula (C-II) or (C-III)
R7SO2Clxe2x80x83xe2x80x83(C-II)
(R7SO2)2Oxe2x80x83xe2x80x83(C-II)
xe2x80x83(where R7 represents an optionally substituted alkyl group or an optionally substituted aryl group) in the presence of a base to give a compound of the general formula (C-IV) (where R7, R3 and R4 have the same meanings as defined above);
(a-2) the step of reacting the compound of the general formula (C-IV) with a compound of the general formula (C-V) (where R1 and R2 have the same meanings as defined above) in the presence of a base and a monovalent or divalent copper salt to give a compound of the general formula (C-VI) (where R1, R2, R3 and R4 have the same meanings as defined above);
(b-1) the step of subjecting the compound of the general formula (C-VI) which is the end product of step (a-2) to halogenation reaction to give a compound of the general formula (D-II) (where R1, R2, R3 and R4 have the same meanings as defined above and Hal represents a halogen atom);
(b-2) the step of subjecting the compound of the general formula (D-II) to thermal cyclization reaction to give a 4-halobenzopyran derivative of the general formula (I) (where R1, R2, R3, R4and Hal have the same meanings as defined above);
(d-1) the step of reacting the compound of the general formula (C-VI), which is the end product of step (a-2), with a compound of the general formula (H-II)
Oxe2x95x90C(OR8)2xe2x80x83xe2x80x83(H-II)
xe2x80x83or a compound of the general formula (H-III)
ClCxe2x95x90O(OR8)xe2x80x83xe2x80x83(H-III)
xe2x80x83(where R1 represents an optionally substituted lower alkyl group) to give a compound of the general formula (H-IV) (where R1, R2, R3, R4 and R8 have the same meanings as defined above);
(d-2) the step of subjecting the compound of the general formula (H-IV) to thermal cyclization reaction to give a compound of the general formula (H-V) (where R1, R2, R3, R4 and R8 have the same meanings as defined above);
(d-3) the step of hydrolyzing the resulting compound of the general formula (H-V) and then subjecting the hydrolyzate to dehydrative condensation with a compound of the general formula (G-III)
R5R6NHxe2x80x83xe2x80x83(G-III)
xe2x80x83(where R5 and R6 which may be the same or different represent a hydrogen atom or an optionally substituted lower alkyl group) to give a 4-substituted benzopyran derivative of the general formula (G-VI) set forth above.
2. A process for producing 4-substituted benzopyran derivatives represented by the general formula (G-VIa) (where R1a represents a lower perfluoroalkyl group, a nitro group or a cyano group; R3a and R4a which may be the same or different represent a hydrogen atom, an optionally substituted lower alkyl group or, when taken together with the carbon atom to which they are bound, represent a polymethylene group or a substituent forming a heterocycle, provided that R3a and R4a are not both a hydrogen atom; R5 and R6 which may be the same or different represent a hydrogen atom or an optionally substituted lower alkyl group) by any one of the schemes (1a) and (2a) containing a plurality of steps as indicated below, namely,
(1a) (1a-1)xe2x86x92(1a-2)xe2x86x92(1a-3)xe2x86x92(1a-4)xe2x86x92(1a-5); and
(2a) (2a-1)xe2x86x92(2a-2)xe2x86x92(2a-3)xe2x86x92(2a-4)xe2x86x92(2a-5)xe2x86x92(1a-5);
(1a-1) the step of reacting a compound of the general formula (IIa) (where X and Y which may be the same or different represent a leaving group such as a halogen atom, an optionally substituted lower alkylsulfonyloxy group or an arylsulfonyloxy group; R1a has the same meaning as defined above) with an olefin of the general formula (IIIa) (where R3a and R4a have the same meanings as defined above) to give a compound of the general formula (IVa) (where Y, R1a, R3a and R4a have the same meanings as defined above);
(1a-2) the step of reacting the resulting compound of the general formula (IVa) with a halogenating agent to give a compound of the general formula (Va) (where Y, R1a, R3a and R4a have the same meanings as defined above, and Hal represents a halogen atom);
(1a-3) the step of reacting the resulting compound of the general formula (Va) with a base to give a compound of the general formula (VIa) (where Y, R1a, R3a, R4a and Hal have the same meanings as defined above);
(1a-4) the step of reacting the resulting compound of the general formula (VIa) with a base to give a compound of the general formula (Ia) (where R1a, R3a, R4a and Hal have the same meanings as defined above);
(1a-5) the step of reacting the resulting compound of the general formula (Ia) with carbon monoxide and a compound of the general formula (G-III)
xe2x80x83R5R6NHxe2x80x83xe2x80x83(G-III)
xe2x80x83(where R5 and R6 which may be the same or different represent a hydrogen atom or an optionally substituted lower alkyl group) in the presence of a metal to give a 4-substituted benzopyran derivative of the general formula (G-VIa) set forth above (where R1a, R3a, R4a, R5 and R6 have the same meanings as defined above);
(2a-1) the step of reacting a compound of the general formula (IIa) with acetylene of the general formula (VIIa) (where R3a and R4a have the same meanings as defined above) to give a compound of the general formula (VIIIa) (where Y, R1a, R3a and R4a have the same meanings as defined above);
(2a-2) the step of treating the resulting compound of the general formula (VIIIa) with a reducing agent to give a compound of the general formula (IXa) (where Y, R1a, R3a and R4a have the same meanings as defined above);
(2a-3) the step of reacting the resulting compound of the general formula (IXa) with a base to give a benzopyran derivative of the general formula (Xa) (where R1a, R3a and R4a have the same meanings as defined above);
(2a-4) the step of reacting the resulting compound of the general formula (Xa) with a halogenating agent to give a 3,4-dihalobenzopyran derivative of the general formula (XIa) (where R1a, R3a and R4a have the same meanings as defined above and Hal represents a halogen atom);
(2a-5) the step of treating the resulting compound of the general formula (XIa) with a base to give a 4-halobenzopyran derivative of the general formula (Ia) set forth above.
3. A process for producing 4-substituted benzopyran derivatives represented by the general formula (G-VIb) (where R1b represents a lower perfluoroalkyl group; R3b and R4b which may be the same or different represent a hydrogen atom, an optionally substituted lower alkyl group or, when taken together with the carbon atom to which they are bound, represent a polymethylene group, provided that R3b and R4b are not both a hydrogen atom; R5 and R6 which may be the same or different represent a hydrogen atom or an optionally substituted lower alkyl group) by any one of the schemes (1b) and (2b) containing a plurality of steps as indicated below, namely,
(1b) (1b-1)xe2x86x92(1b-2)xe2x86x92(1b-3)xe2x86x92(1b-4)xe2x86x92(1b-5); and
(2b)xe2x86x92(2b-1)xe2x86x92(2b-2)xe2x86x92(2b-3)xe2x86x92(2ba-4)xe2x86x92(2b-5)xe2x86x92(1b-5);
(1b-1) the step of reacting a compound of the general formula (IIb) (where X and Y which may be the same or different represent a leaving group such as a halogen atom, an optionally substituted lower alkylsulfonyloxy group or an arylsulfonyloxy group; R1b has the same meaning as defined above) with an olefin of the general formula (IIIb) (where R3b and R4b have the same meanings as defined above) to give a compound of the general formula (IVb) (where Y, R1b, R3b and R4b have the same meanings as defined above); (1b-2) the step of reacting the resulting compound of the general formula (IVb) with a halogenating agent to give a compound of the general formula (Vb) (where Y, R1b, R3b and R4b have the same meanings as defined above, and Hal represents a halogen atom);
(1b-3) the step of reacting the resulting compound of the general formula (Vb) with a base to give a compound of the general formula (VIb) (where Y, R1b, R3b, R4b and Hal have the same meanings as defined above);
(1b-4) the step of reacting the resulting compound of the general formula (VIb) with a base to give a compound of the general formula (Ib) (where R1b, R3b, R4b and Hal have the same meanings as defined above);
(Ib-5) the step of reacting the resulting compound of the general formula (Ib) with carbon monoxide and a compound of the general formula (G-III)
R5R6NHxe2x80x83xe2x80x83(G-III)
xe2x80x83(where R5 and R6 which may be the same or different represent a hydrogen atom or an optionally substituted lower alkyl group) in the presence of a metal to give a 4-substituted benzopyran derivative of the general formula (G-VIb) set forth above (where R1b, R3b, R4b, R5 and R6 have the same meanings as defined above);
(2b-1) the step of reacting a compound of the general formula (IIb) with acetylene of the general formula (VIIb) (where R3b and R4b have the same meanings as defined above) to give a compound of the general formula (VIIIb) (where Y, R1b, R3b and R4b have the same meanings as defined above);
(2b-2) the step of treating the resulting compound of the general formula (VIIIb) with a reducing agent to give a compound of the general formula (IXb) (where Y, R1b, R3b and R4b have the same meanings as defined above);
(2b-3) the step of reacting the resulting compound of the general formula (IXb) with a base to give a benzopyran derivative of the general formula (Xb) (where R1b, R3b and R4b have the same meanings as defined above);
(2b-4) the step of reacting the resulting compound of the general formula (Xb) with a halogenating agent to give a 3,4-dihalobenzopyran derivative of the general formula (XIb) (where R1b, R3b, R4b and Hal have the same meanings as defined above);
(2b-5) the step of treating the resulting compound of the general formula (XIb) with a base to give a 4-halobenzopyran derivative of the general formula (Ib) set forth above.
4. A process for producing 4-substituted benzopyran derivatives represented by the general formula (G-VIc) (where R1b represents a lower perfluoroalkyl group; R3c and R4c which are the same represent a lower alkyl group or a lower fluoroalkyl group; R5c represents a hydrogen atom and R6 represents an optionally substituted lower alkyl group) by any one of the schemes (1c) and (2c) containing a plurality of steps as indicated below, namely,
(1c) (1c-1)xe2x86x92(1c-2)xe2x86x92(1c-3)xe2x86x92(1c-4)xe2x86x92(1c-5); and
(2c) (2c-1)xe2x86x92(2c-2)xe2x86x92(2c-3)xe2x86x92(2c-4)xe2x86x92(2c-5)xe2x86x92(1c-5);
(1c-1) the step of reacting a compound of the general formula (IIb) (where X and Y which may be the same or different represent a leaving group such as a halogen atom, an optionally substituted lower alkylsulfonyloxy group or an arylsulfonyloxy group; R1b has the same meaning as defined above) with an olefin of the general formula (IIIc) (where R3c and R4c have the same meanings as defined above) to give a compound of the general formula (IVc) (where Y, R1b, R3c and R4c have the same meanings as defined above);
(1c-2) the step of reacting the resulting compound of the general formula (IVc) with a halogenating agent to give a compound of the general formula (Vc) (where Y, R1b, R3c and R4c have the same meanings as defined above, and Hal represents a halogen atom);
(1c-3) the step of reacting the resulting compound of the general formula (Vc) with a base to give a compound of the general formula (VIc) (where Y, R1b, R3c and R4c have the same meanings as defined above, and Hal represents a halogen atom);
(1c-4) the step of reacting the resulting compound of the general formula (VIc) with a base to give a compound of the general formula (Ic) (where R1b, R3c, R4c and Hal have the same meanings as defined above);
(Ic-5) the step of reacting the resulting compound of the general formula (Ic) with carbon monoxide and a compound of the general formula (G-IIIc)
R5cR6aNHxe2x80x83xe2x80x83(G-IIIc)
xe2x80x83(where R5c represents a hydrogen atom and R6a represents an optionally substituted lower alkyl group) in the presence of a metal to give a 4-substituted benzopyran derivative of the general formula (G-VIc) set forth above;
(2c-1) the step of reacting a compound of the general formula (IIb) with acetylene of the general formula (VIIc) (where R3c and R4c have the same meanings as defined above) to give a compound of the general formula (VIIIc) (where Y, R1b, R3c and R4c have the same meanings as defined above);
(2c-2) the step of treating the resulting compound of the general formula (VIIIc) with a reducing agent to give a compound of the general formula (IXc) (where Y, R1b, R3c and R4c have the same meanings as defined above);
(2c-3) the step of reacting the resulting compound of the general formula (IXc) with a base to give a benzopyran derivative of the general formula (Xc) (where R1b, R3c and R4c have the same meanings as defined above);
(2c-4) the step of reacting the resulting compound of the general formula (Xc) with a halogenating agent to give a 3,4-dihalobenzopyran derivative of the general formula (XIc) (where R1b, R3c, R4c and Hal have the same meanings as defined above);
(2c-5) the step of treating the resulting compound of the general formula (XIc) with a base to give a 4-halobenzopyran derivative of the general formula (Ic) set forth above.
5. A process for producing 4-substituted benzopyran derivatives represented by the general formula (G-VId) (where R1b represents a lower perfluoroalkyl group; R5c represents a hydrogen atom; and R6b represents a lower alkyl group which may optionally have a cyano group) by any one of the schemes (1d) and (2d) containing a plurality of steps as indicated below, namely,
(1d) (1d-1)xe2x86x92(1d-2)xe2x86x92(1d-3)xe2x86x92(1d-4)xe2x86x92(1d-5); and
(2d) (2d-1)xe2x86x92(2d-2)xe2x86x92(2d-3)xe2x86x92(2d-4)xe2x86x92(2d-5)xe2x86x92(1d-5);
(1d-1) the step of reacting a compound of the general formula (IId) (where X and Y which may be the same or different represent a leaving group such as a halogen atom, an optionally substituted lower alkylsulfonyloxy group or an arylsulfonyloxy group; R1b has the same meaning as defined above) with an olefin of the general formula (IIId) set forth below to give a compound of the general formula (IVd) (where Y and R1b have the same meanings as defined above);
(1d-2) the step of reacting the resulting compound of the general formula (IVd) with a halogenating agent to give a compound of the general formula (Vd) (where Y and R1b have the same meanings as defined above, and Hal represents a halogen atom);
(1d-3) the step of reacting the resulting compound of the general formula (Vd) with a base to give a compound of the general formula (VId) (where Y, R1b and Hal have the same meanings as defined above);
(1d-4) the step of reacting the resulting compound of the general formula (VId) with a base to give a 4-halobenzopyran derivative of the general formula (Id) (where R1b and Hal have the same meanings as defined above);
(Id-5) the step of reacting the resulting compound of the general formula (Id) with carbon monoxide and a compound of the general formula (G-IIId)
R5cR6bNHxe2x80x83xe2x80x83(G-IIId)
xe2x80x83(where R5c represents a hydrogen atom and R6b represents a lower alkyl group which may optionally have a cyano group) in the presence of a metal to give a 4-substituted benzopyran derivative of the general formula (G-VId) set forth above;
(2d-1) the step of reacting a compound of the general formula (IId) with acetylene of the general formula (VIId) to give a compound of the general formula (VIIId) (where Y and R1b have the same meanings as defined above);
(2d-2) the step of treating the resulting compound of the general formula (VIIId) with a reducing agent to give a compound of the general formula (IXd) (where Y and R1b have the same meanings as defined above);
(2d-3) the step of reacting the resulting compound of the general formula (IXd) with a base to give a benzopyran derivative of the general formula (Xd) (where R1b has the same meaning as defined above);
(2d-4) the step of reacting the resulting compound of the general formula (Xd) with a halogenating agent to give a 3,4-dihalobenzopyran derivative of the general formula (XId) (where R1b and Hal have the same meanings as defined above);
(2d-5) the step of treating the resulting compound of the general formula (XId) with a base to give a 4-halobenzopyran derivative of the general formula (Id) (where R1b and Hal have the same meanings as defined above).
6. A process for producing 4-substituted benzopyran derivatives represented by the general formula (G-VIe) (where R1e represents a trifluoromethyl group or a pentafluoroethyl group; R5c represents a hydrogen atom; R6d represents a cyanoethyl group) by any one of the schemes (1e) and (2e) containing a plurality of steps as indicated below, namely,
(1e) (1e-1)xe2x86x92(1e-2)xe2x86x92(1e-3)xe2x86x92(1e-4)xe2x86x92(1e-5); and
(2e) (2e-1)xe2x86x92(2e-2)xe2x86x92(2e-3)xe2x86x92(2e-4)xe2x86x92(2e-5)xe2x86x92(1e-5);
(1e-1) the step of reacting a compound of the general formula (IIe) (where R1e has the same meaning as defined above) with an olefin of the general formula (IIId) set forth below to give a compound of the general formula (IVe) (where R1e has the same meaning as defined above);
(1e-2) the step of reacting the resulting compound of the general formula (IVe) with a halogenating agent to give a compound of the general formula (Ve) (where R1e has the same meaning as defined above; Hal represents a halogen atom);
(1e-3) the step of reacting the resulting compound of the general formula (Ve) with a base to give a compound of the general formula (VIe) (where R1e and Hal have the same meanings as defined above);
(1e-4) the step of reacting the resulting compound of the general formula (VIe) with a base to give a 4-halobenzopyran derivative of the general formula (Ie) (where R1e and Hal have the same meanings as defined above);
(Ie-5) the step of reacting the resulting compound of the general formula (Ie) with carbon monoxide and a compound of the general formula (G-IIIe)
R5cR6dNHxe2x80x83xe2x80x83(G-IIIe)
(where R5c represents a hydrogen atom and R6d represents a cyanoethyl group) in the presence of a metal to give a 4-substituted benzopyran derivative of the general formula (G-VIe) set forth above;
(2e-1) the step of reacting a compound of the general formula (IIe2) (where R1e has the same meaning as defined above) with acetylene of the general formula (VIId) set forth below to give a compound of the general formula (VIIIe) (where R1e has the same meaning as defined above);
(2e-2) the step of treating the resulting compound of the general formula (VIIIe) with a reducing agent to give a compound of the general formula (IXe) (where R1e has the same meaning as defined above);
(2e-3) the step of reacting the resulting compound of the general formula (IXe) with a base to give a benzopyran derivative of the general formula (Xd) (where R1d has the same meaning as defined above);
(2e-4) the step of reacting the resulting compound of the general formula (Xd) with a halogenating agent to give a 3,4-dihalobenzopyran derivative of the general formula (XIe) (where R1e and Hal have the same meanings as defined above);
(2e-5) the step of treating the resulting compound of the general formula (XIe) with a base to give a 4-halobenzopyran derivative of the general formula (Ie) set forth above.
7. A process according to scheme (3) or (4) in Process 1 for producing 4-substituted benzopyran derivatives represented by the general formula (G-VIg) [where R1g and R2g which may be the same or different represent a hydrogen atom, an optionally substituted lower alkyl group, an optionally substituted lower alkoxy group, an optionally substituted lower alkoxycarbonyl group, an optionally substituted lower alkylsulfonyl group, an optionally substituted arylsulfonyl group, a halogen atom, a nitro group, a cyano group or NYaYb (where Ya and Yb which may be the same or different each represent a hydrogen atom, an optionally substituted lower alkyl group, an optionally substituted lower alkoxycarbonyl group, an acyl group, an optionally substituted lower alkylsulfonyl group or an optionally substituted arylsulfonyl group or, when taken together with the nitrogen atom to which they are bound, may form a 3- to 8-membered ring); R3g and R4g which may be the same or different represent a hydrogen atom or an optionally substituted xcex1-haloalkyl group, provided that they are not both a hydrogen atom; R5 and R6 which may be the same or different represent a hydrogen atom or an optionally substituted lower alkyl group] by the steps of:
reacting an alcohol of the general formula (C-Ig) (where R3g and R4g have the same meanings as defined above) with a compound of the general formula (C-II) or (C-III)
R7SO2Clxe2x80x83xe2x80x83(C-II)
(R7SO2)2Oxe2x80x83xe2x80x83(C-III)
xe2x80x83(where R7 represents an optionally substituted alkyl group or an optionally substituted aryl group) in the presence of a base to give a compound of the general formula (C-IVg) (where R7, R3g and R4g have the same meanings as defined above);
reacting the compound of the general formula (C-IVg) with a compound of the general formula (C-Vg) (where R1g and R2g have the same meanings as defined above) in the presence of a base and a monovalent or divalent copper salt to give a compound of the general formula,(G-Ig) (where R1g, R2g, R3g and R4g have the same meanings as defined above);
reacting the compound of the general formula (G-Ig) with carbon dioxide in the presence of a base to give a compound of the general formula (G-IIg) (where R1g, R2g, R3g and R4g have the same meanings as defined above) or a salt thereof;
reacting the compound of the general formula (G-IIg) or salt thereof with a compound of the general formula (G-III)
R5R6NHxe2x80x83xe2x80x83(G-III)
xe2x80x83(where R5 and R6 which may be the same or different represent a hydrogen atom or an optionally substituted lower alkyl group) to give a compound of the general formula (G-Vg) (where R1g, R2g, R3g, R4g, R5 and R6 have the same meanings as defined above); or alternatively reacting the compound of the general formula (G-Ig) (where R1g, R2g, R3g and R4g have the same meanings as defined above) with a compound of the general formula (G-IVa) (where R5 and R6 which may be the same or different represent a hydrogen atom or an optionally substituted lower alkyl group) or a compound of the general formula (G-IVb)
R6aNCOxe2x80x83xe2x80x83(G-IVb)
xe2x80x83(where R6a represents an optionally substituted lower alkyl group) in the presence of a base to give a compound of the general formula (G-Vg) (where R1g, R2, R3g, R4g, R5 and R6 have the same meanings as defined above); and
subjecting the compound of the general formula (G-Vg) to thermal cyclization reaction.
8. A process according to scheme (3) or (4) in Process 1 or a process according to Process 7 for producing 4-substituted benzopyran derivatives represented by the general formula (G-VIh) set forth below, wherein R1 and R2 in the general formula (G-VI) which may be the same or different represent a hydrogen atom, an optionally substituted lower alkyl group, an optionally substituted lower alkoxy group, an optionally substituted lower alkoxycarbonyl group, an optionally substituted lower alkylsulfonyl group, an optionally substituted arylsulfonyl group, a halogen atom, a nitro group, a cyano group or NYaYb (where Ya and Yb which may be the same or different each represent a hydrogen atom, an optionally substituted lower alkyl group, an optionally substituted lower alkoxycarbonyl group, an acyl group, an optionally substituted lower alkylsulfonyl group or an optionally substituted arylsulfonyl group or, when taken together, may form a 3- to 8-membered ring); R3 and R4 each represent a fluoromethyl group; and R5 and R6 which may be the same or different represent a hydrogen atom or an optionally substituted lower alkyl group.
9. A process according to scheme (3) or (4) in Process 1 or a process according to Process 7 for producing 4-substituted benzopyran derivatives represented by the general formula (G-VIi) set forth below, wherein R1 in the general formula (G-VI) represents a 6-trifluoromethyl group or a 6-pentafluoroethyl group; R2 represents a hydrogen atom; R3 and R4 each represent a fluoromethyl group; and R5 and R6 which may be the same or different represent a hydrogen atom or an optionally substituted lower alkyl group.
10. A process according to scheme (3) or (4) in Process 1 or a process according to Process 7 for producing 4-substituted benzopyran derivatives represented by the general formula (G-VIj) set forth below, wherein R1 in the general formula (G-VI) represents a 6-trifluoromethyl group or a 6-pentafluoroethyl group; R2 represents a hydrogen atom; R3 and R4 each represent a fluoromethyl group; and R5 represents a hydrogen atom and R6 represents a 2-cyanoethyl group.
11. A process for producing 4-substituted benzopyran derivatives represented by the general formula (G-VIg) [where R1g and R2g which may be the same or different represent a hydrogen atom, an optionally substituted lower alkyl group, an optionally substituted lower alkoxy group, an optionally substituted lower alkoxycarbonyl group, an optionally substituted lower alkylsulfonyl group, an optionally substituted arylsulfonyl group, a halogen atom, a nitro group, a cyano group or NYaYb (where Ya and Yb which may be the same or different each represent a hydrogen atom, an optionally substituted lower alkyl group, an optionally substituted lower alkoxycarbonyl group, an acyl group, an optionally substituted lower alkylsulfonyl group or an optionally substituted arylsulfonyl group or, when taken together with the nitrogen atom to which they are bound, may form a 3- to 8-membered ring); R3g and R4g which may be the same or different represent a hydrogen atom or an optionally substituted xcex1-haloalkyl group, provided that they are not both a hydrogen atom; R5 and R6 which may be the same or different represent a hydrogen atom or an optionally substituted lower alkyl group], wherein a compound represented by the general formula (G-VIg) (where R1g, R2g, R3g, R4g, R5 and R6 have the same meanings as defined above).
12. A process according to Process 11 for producing 4-substituted benzopyran derivatives represented by the general formula (G-VIl) set forth below, wherein R1g and R2g in the general formula (G-VIg) which may be the same or different represent a hydrogen atom, an optionally substituted lower alkyl group, an optionally substituted lower alkoxy group, an optionally substituted lower alkoxycarbonyl group, an optionally substituted lower alkylsulfonyl group, an optionally substituted arylsulfonyl group, a halogen atom, a nitro group, a cyano group or NYaYb (where Ya and Yb which may be the same or different each represent a hydrogen atom, an optionally substituted lower alkyl group, an optionally substituted lower alkoxycarbonyl group, an acyl group, an optionally substituted lower alkylsulfonyl group or an optionally substituted arylsulfonyl group or, when taken together with the nitrogen atom to which they are bound, may form a 3- to 8-membered ring); R3g and R4g each represent a fluoromethyl group; R5 and R6 which may be the same or different represent a hydrogen atom or an optionally substituted lower alkyl group.
13. A process according to Process 11 for producing 4-substituted benzopyran derivatives represented by the general formula (G-VIm) set forth below, wherein R1g in the general formula (G-VIg) represents a 6-trifluoromethyl group or a 6-pentafluoroethyl group; R2g represents a hydrogen atom; R3g and R4g each represent a fluoromethyl group; and R5 and R6 which may be the same or different represent a hydrogen atom or an optionally substituted lower alkyl group.
14. A process according to Process 11 for producing 4-substituted benzopyran derivatives represented by the general formula (G-VIn) set forth below, wherein R1g in the general formula (G-VIg) represents a 6-trifluoromethyl group or a 6-pentafluoroethyl group; R2g represents a hydrogen atom; R3g and R4g each represent a fluoromethyl group; and R5 represents a hydrogen atom and R6 represents a 2-cyanoethyl group.
15. A process according to scheme (5) or (6) in Process 1 for producing 4-substituted benzopyran derivatives represented by the general formula (Iz) set forth below [where R1g and R2g which may be the same or different represent a hydrogen atom, an optionally substituted lower alkyl group, a halogen atom, an optionally substituted lower alkoxy group, NYaYb (where Ya and Yb which may be the same or different each represent a hydrogen atom, an optionally substituted lower alkyl group, an optionally substituted lower alkoxycarbonyl group, an acyl group, an optionally substituted lower alkylsulfonyl group or an optionally substituted arylsulfonyl group or, when taken together with the nitrogen atom to which they are bound, may form a 3- to 8-membered ring), a nitro group, a cyano group, an optionally substituted lower alkoxycarbonyl group, an optionally substituted lower alkylsulfonyl group or an optionally substituted arylsulfonyl group; Hal represents a halogen atom] by the steps of:
reacting an alcohol of the general formula (C-Ia) with a compound of the general formula (C-II) or (C-III)
R7SO2Clxe2x80x83xe2x80x83(C-II)
(R7SO2)2Oxe2x80x83xe2x80x83(C-III)
xe2x80x83(where R7 represents an optionally substituted lower alkyl group or an optionally substituted aryl group) in the presence of a base to give a compound of the general formula (C-IVa) (where R7 has the same meaning as defined above);
reacting the compound of the general formula (C-IVa) with a compound of the general formula (C-Vg) (where R1g and R2g have the same meanings as defined above) in the presence of a base and a monovalent or divalent copper salt to give a compound of the general formula (G-VIa) (where R1g and R2g have the same meanings as defined above);
subjecting the compound of the general formula (G-VIa) to halogenation reaction to give a compound of the general formula (D-IIa) (where R1g, R2g and Hal have the same meanings as defined above); and
subjecting the compound of the general formula (D-IIa) to thermal cyclization reaction.
16. A process according to scheme (5) or (6) in Process 1 for producing 4-substituted benzopyran derivatives represented by the general formula (Iy) set forth below (where R1 in the general formula (I) represents a 6-trifluoromethyl group or a 6-pentafluoroethyl group; R2 represents a hydrogen atom; R3 and R4 both represent a fluoromethyl group; X is a bromine atom) by the steps of:
reacting an alcohol of the general formula (C-Ia) with a compound of the general formula (C-II) or (C-III)
R7SO2Clxe2x80x83xe2x80x83(C-II)
(R7SO2)2Oxe2x80x83xe2x80x83(C-III)
xe2x80x83(where R7 represents an optionally substituted lower alkyl group or an optionally substituted aryl group) in the presence of a base to give a compound of the general formula (C-IVa) (where R7 has the same meaning as defined above);
reacting the compound of the general formula (C-IVa) with a 4-substituted phenol derivative of the general formula (C-Va) (where R1e has the same meaning as defined above) in the presence of a base and a monovalent or divalent copper salt to give a compound of the general formula (G-VIb) (where R1e has the same meaning as defined above);
subjecting the compound of the general formula (G-VIb) to bromination reaction to give a compound of the general formula (D-IIb) (where R1e has the same meaning as defined above); and
subjecting the compound of the general formula (G-IIb) to thermal cyclization reaction.
17. A process according to scheme (5) or (6) in Process 1 for producing 4-substituted benzopyran derivatives represented by the general formula (G-VIz) set forth below, wherein R1 in the general formula (G-VI) represents a 6-trifluoromethyl group or a 6-pentafluoroethyl group; R2 represents a hydrogen atom; R3 and R4 each represent a fluoromethyl group; and R5 and R6 which may be the same or different represent a hydrogen atom or an optionally substituted lower alkyl group.
18. A process according to scheme (5) or (6) in Process 1 for producing 4-substituted benzopyran derivatives represented by the general formula (G-VIy) set forth below, wherein R1 in the general formula (G-VI) represents a 6-trifluoromethyl group or a 6pentafluoroethyl group; R2 represents a hydrogen atom; R3 and R4 each represent a fluoromethyl group; and R5 represents a hydrogen atom and R6 represents a 2-cyanoethyl group.
19. A process according to scheme (5) or (6) in Process 1, which uses a compound of the general formula (C-IVb) as obtained by reacting methanesulfonyl chloride of the general formula (C-II) where R7 is a methyl group with a compound of the general formula (C-I) where R3 and R4 are each a fluoromethyl group.
20. A process according to scheme (5) or (6) in Process 1, which uses a compound of the general formula (C-IVc) (where Tol represents a tolyl group) that is obtained by reacting p-toluenesulfonyl chloride of the general formula (C-II) where R7 is a p-tolyl group with a compound of the general formula (C-I) where R3 and R4 are each a fluoromethyl group in the presence of a base.
21. A process according to scheme (5) or (6) in Process 1, which uses a compound of the general formula (C-VIb) (where R1e has the same meaning as defined above) that is obtained by reacting a compound of the general formula (C-Va) set forth below (where R1e has the same meaning as defined above; R1 in the general formula (C-V) is a 4-trifluoromethyl group or a 4-pentafluoroethyl group and R2 is a hydrogen atom) with a compound of the general formula (C-IVb) or (C-IVc) set forth below, wherein Tol represents a p-tolyl group.
22. A process according to scheme (5) or (6) in Process 1, which uses a compound of the general formula (D-IIb) (where R1e has the same meaning as defined above) that is obtained by brominating a compound of the general formula (C-VIb) set forth below (where R1e has the same meaning as defined above; R1 in the general formula (C-VI) is a 4-trifluoromethyl group or a 4-pentafluoroethyl group; R2 is a hydrogen atom; R3 and R4 are both a fluoromethyl group).
23. A process according to scheme (5) or (6) in Process 1, which uses a 4-bromobenzopyran derivative of the general formula (Iq) (where R1e has the same meaning as defined above) that is obtained by subjecting a compound of the general formula (D-IIb) set forth below (where R1e has the same meaning as defined above; R1 in the general formula (D-II) is a 4-trifluoromethyl group or a 4-pentafluoroethyl group; R2 is a hydrogen atom; R3 and R4 are both a fluoromethyl group; X is a bromine atom) to thermal cyclization reaction.
The general formula (G-1) and the general formula (C-VI) represent substantially the same compound. R1 and R1g represent substantially the same group, so do R2 and R2g.
The general formula (C-V) and the general formula (C-Vg) represent substantially the same compound.
The general formulae (C-VIe), (C-VIj) and (C-VIy) represent substantially the same compound.
As mentioned above, the present invention relates to a process for producing 4-substituted benzopyran derivatives represented by the general formula (G-VI) [where R1 and R2 which may be the same or different represent a hydrogen atom, an optionally substituted lower alkyl group, an optionally substituted lower alkoxy group, an optionally substituted lower alkoxycarbonyl group, an optionally substituted lower alkylsulfonyl group, an optionally substituted arylsulfonyl group, a halogen atom, a nitro group, a cyano group or NYaYb (where Ya and Yb which may be the same or different each represent a hydrogen atom, an optionally substituted lower alkyl group, an optionally substituted lower alkoxycarbonyl group, an acyl group, an optionally substituted lower alkylsulfonyl group or an optionally substituted arylsulfonyl group or, when taken together with the nitrogen atom to which they are bound, may form a 3- to 8-membered ring) or, when taken together, represent a substituent xe2x95x90Nxe2x95x90Oxe2x80x94Nxe2x95x90; R3 and R4 which may be the same or different represent a hydrogen atom or an optionally substituted lower alkyl group or, when taken together with the carbon atom to which they are bound, represent a polymethylene group or a substituent forming a heterocycle, provided that R3 and R4 are not both a hydrogen atom; R5 and R6 which may be the same or different represent a hydrogen atom or an optionally substituted lower alkyl group] by any one of the schemes (1), (2), (3), (4), (5) and (6) containing a plurality of steps as indicated below, namely,
(1): (1-1)xe2x86x92(1-2)xe2x86x92(1-3)xe2x86x92(1-4)xe2x86x92(1-5):
(2): (2-1)xe2x86x92(2-2)xe2x86x92(2-3)xe2x86x92(2-4)xe2x86x92(2-5)xe2x86x92(1-5);
(3): (3-1)xe2x86x92(3-2);
(4): (4-1)xe2x86x92(4-2);
(5): (a-1)xe2x86x92(a-2)xe2x86x92(b-1)xe2x86x92(b-2)xe2x86x92(1-5); and
(6): (a-1)xe2x86x92(a-2)xe2x86x92(d-1)xe2x86x92(d-2)xe2x86x92(d-3).
Referring to the 4-substituted benzopyran derivatives represented by the general formula (G-VI), examples of the optionally substituted lower alkyl group as R1 and R2 include a lower alkyl group, a lower haloalkyl group, a lower perfluoroalkyl group, a lower alkyl group having a halogen atom as a substituent, and an xcex1-haloalkyl group; examples of the optionally substituted lower alkoxy group as R1 and R2 include a lower alkoxy group and a lower haloalkoxy group; examples of NYaYb as R1 and R2 include an amino group and an acylamino group.
Examples of the optionally substituted lower alkyl group as R3 and R4 include a lower alkyl group, a substituted lower alkyl group, a lower fluoroalkyl group, a lower alkyl group having a halogen atom as a substituent, and an xcex1-haloalkyl group.
On the pages that follow, the practice of the present invention is described for six different schemes grouped in three, the first consisting of schemes (1) and (2), the second being schemes (3) and (4), and the third being schemes (5) and (6).
A. Schemes (1) and (2):
Speaking of the process according to schemes (1) and (2), the preferred substituents in the 4-substituted benzopyran derivatives of the general formula (G-VI) are exemplified by the following.
Preferably, R1 and R2 which may be the same or different represent a hydrogen atom, a lower alkyl group, a lower haloalkyl group, a halogen atom, a lower haloalkoxy group, an amino group, an acylamino group, a nitro group, a cyano group, an alkoxycarbonyl group, an optionally substituted lower alkylsulfonyl group, an arylsulfonyl group or, when taken together, represent a substituent xe2x95x90Nxe2x80x94Oxe2x80x94Nxe2x95x90.
Preferably, R3 and R4 which maybe the same or different represent a hydrogen atom or an optionally substituted lower alkyl group or, when taken together with the carbon atom to which they are bound, represent a polymethylene group or a substituent forming a heterocycle, provided that R3 and R4 are not both a hydrogen atom.
Preferably, R5 and R6 which may be the same or different represent a hydrogen atom or an optionally substituted lower alkyl group.
In schemes (1) and (2), the term xe2x80x9chalogen atomxe2x80x9d means a fluorine atom, a chlorine atom, a bromine atom or an iodine atom.
In schemes (1) and (2), the lower alkyl group means a straight-chained or branched alkyl group having 1-4 carbon atoms or a cyclic alkyl group having 3-6 carbon atoms; examples include a methyl group, an ethyl group, a n-propyl group, a n-butyl group, an i-propyl group, an i-butyl group, a sec-butyl group, a tert-butyl group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group and a cyclohexyl group.
In schemes (1) and (2), the lower alkoxy group means a straight-chained or branched alkoxy group having 1-4 carbon atoms or a cyclic alkoxy group having 3-6 carbon atoms; examples include a methoxy group, an ethoxy group, a n-propoxy group, a n-butoxy group, an i-propoxy group, an i-butoxy group, a sec-butoxy group, a tert-butoxy group, a cyclopropoxy group, a cyclobutoxy group, a cyclopentoxy group and a cyclohexoxy group.
The lower haloalkyl group as R1 and R2 means a straight-chained or branched alkyl group having 1-4 carbon atoms or a cyclic alkyl group having 3-6 carbon atoms, in which at least one hydrogen atom is replaced by a halogen atom; examples include a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a fluoroethyl group, a difluoroethyl group, a trifluoroethyl group, a tetrafluoroethyl group, a pentafluoroethyl group, a n-fluoropropyl group, a n-difluoropropyl group, a n-trifluoropropyl group, a n-tetrafluoropropyl group, a n-pentafluoropropyl group, a n-hexafluoropropyl group, a n-heptafluoropropyl group, a n-fluorobutyl group, a n-difluorobutyl group, a n-trifluorobutyl group, a n-tetrafluorobutyl group, a n-pentafluorobutyl group, a n-hexafluorobutyl group, a n-heptafluorobutyl group, a n-octafluorobutyl group, a n-nonafluorobutyl group, an i-fluoropropyl group, an i-difluoropropyl group, an i-trifluoropropyl group, an i-tetrafluoropropyl group, an i-pentafluoropropyl group, an i-hexafluoropropyl group, an i-heptafluoropropyl group, an i-fluorobutyl group, an i-difluorobutyl group, an i-trifluorobutyl group, an i-tetrafluorobutyl group, an i-pentafluorobutyl group, an i-hexafluorobutyl group, an i-heptafluorobutyl group, an i-octafluorobutyl group, an i-nonafluorobutyl group, a sec-fluorobutyl group, a sec-difluorobutyl group, a sec-trifluorobutyl group, a sec-tetrafluorobutyl group, a sec-pentafluorobutyl group, a sec-hexafluorobutyl group, a sec-heptafluorobutyl group, a sec-octafluorobutyl group, a sec-nonafluorobutyl group, a tert-fluorobutyl group, a tert-difluorobutyl group, a tert-trifluorobutyl group, a tert-tetrafluorobutyl group, a tert-pentafluorobutyl group, a tert-hexafluorobutyl group, a tert-heptafluorobutyl group, a tert-octafluorobutyl group, a tert-nonafluorobutyl group, a fluorocyclopropyl group, a difluorocyclopropyl group, a trifluorocyclopropyl group, a tetrafluorocyclopropyl group, a pentafluorocyclopropyl group, affluorocyclobutyl group, a difluorocyclobutyl group, a trifluorocyclobutyl group, a tetrafluorocyclobutyl group, a pentafluorocyclobutyl group, a hexafluorocyclobutyl group, a heptafluorocyclobutyl group, a fluorocyclopentyl group, a difluorocyclopentyl group, a trifluorocyclopentyl group, a tetrafluorocyclopentyl group, a pentafluorocyclopentyl group, a hexafluorocyclopentyl group, a heptafluorocyclopentyl group, an octafluorocyclopentyl group, a nonafluorocyclopentyl group, a fluorocyclohexyl group, a difluorocyclohexyl group, a trifluorocyclohexyl group, a tetrafluorocyclohexyl group, a pentafluorocyclohexyl group, a hexafluorocyclohexyl group, a heptafluorocyclohexyl group, an octafluorocyclohexyl group, a nonafluorocyclohexyl group, a decafluorocyclohexyl group, and an undecafluorocyclohexyl group.
The lower perfluoroalkyl group as R1 means a straight-chained or branched perfluoroalkyl group having 1-4 carbon atoms or a cyclic perfluoroalkyl group having 3-6 carbon atoms; examples include a trifluoromethyl group, a pentafluoroethyl group, a n-heptafluoropropyl group, a n-nonafluorobutyl group, an i-heptafluoropropyl group, an i-nonafluorobutyl group, a sec-nonafluorobutyl group, a tert-nonafluorobutyl group, a pentafluorocyclopropyl group, a heptafluorocyclobutyl group, a nonafluorocyclopentyl group and an undecafluorocyclohexyl. group.
Examples of the optionally substituted lower alkylsulfonyloxy group as X and Y include a methanesulfonyloxy group and a trifluoromethanesulfonyloxy group.
Examples of the arylsulfonyloxy group as X and Y include a benzenesulfonyloxy group and a p-toluenesulfonyloxy group.
The lower haloalkoxy group as R1 and R2 means a straight-chained or branched alkoxy group having 1-4 carbon atoms or a cyclic alkoxy group having 3-6 carbon atoms, in which at least one hydrogen atom is replaced by a halogen atom; examples include a trifluoromethoxy group, a fluoroethoxy group, a difluoroethoxy group, a trifluoroethoxy group, a tetrafluoroethoxy group, a pentafluoroethoxy group, a n-fluoropropoxy group, a n-difluoropropoxy group, a n-trifluoropropoxy group, a n-tetrafluoropropoxy group, a n-pentafluoropropoxy group, a n-hexafluoropropoxy group, a n-heptafluoropropoxy group, a n-fluorobutoxy group, a n-difluorobutoxy group, a n-trifluorobutoxy group, a n-tetrafluorobutoxy group, a n-pentafluorobutoxy group, a n-hexafluorobutoxy group, a n-heptafluorobutoxy group, a n-octafluorobutoxy group, a n-nonafluorobutoxy group, an i-fluoropropoxygroup, an i-difoluoropropoxy group, an i-trifluoropropoxy group, an i-tetrafluoropropoxy group, an i-pentafluoropropoxy group, an i-hexafluoropropoxy group, an i-heptafluoropropoxy group, an i-fluorobutoxy group, an i-difluorobut oxy group, an i-trifluorobutoxy group, an 1-tetrafluorobutoxy group, an i-pentafluorobutoxy group, an i-hexafluorobutoxy group, an i-heptafluorobutoxy group, an i-octafluorobutoxy group, an i-nonafluorobutoxy group, a sec-fluorobutoxy group, a sec-difluorobutoxy group, a sec-trifluorobutoxy group, a sec-tetrafluorobutoxy group, a sec-pentafluorobutoxy group, a sec-hexafluorobutoxy group, a sec-peptafluorobutoxy group, a sec-octafluorobutoxy group, a sec-nonafluorobutoxy group, a tert-fluorobutoxy group, a tert-difluorobutoxy group, a tert-trifluorobutoxy group, a tert-tetrafluorobutoxy group, a tert-pentafluorobutoxy group, a tert-hexafluorobutoxy group, a tert-heptafluorobutoxy group, a tert-octafluorobuoxty group, a tert-nonafluorobutoxy group, a fluorocyclopropoxy group, a difluorocyclopropoxy group, a trifluorocyclopropoxy group, a tetrafluorocyclopropoxy group, a pentafluorocyclopropoxy group, a fluorocyclobutoxy group, a difluorocyclobutoxy group, a trifluorocyclobutoxy group, a tetrafluorocyclobutoxy group, a pentafluorocyclobutoxy group, a hexafluorocyclobutoxy group, a heptafluorocyclobutoxy group, a fluorocyclopentoxy group, a difluorocyclopentoxy group, a trifluorocyclopentoxy group, a tetrafluorocyclopentoxy group, a pentafluorocyclopentoxy group, a hexafluorocyclopentoxy group, a heptafluorocyclopentoxy group, an octafluorocyclopentoxy group, a nonafluorocyclopentoxy group, a fluorocyclohexoxy group, a difluorocyclohexoxy group, a trifluorocyclohexoxy group, a d tetrafluorocyclohexoxy group, a pentafluorocyclohexoxy group, a hexafluorocyclohexoxy group, a heptafluorocyclohexoxy group, an octafluorocyclohexoxy group, a nonafluorocyclohexoxy group, a decafluorocyclohexoxy group, and an undecafluorocyclohexoxy group.
The acylamino group as R1 and R2 means an amino group in which one of the hydrogen atoms present is replaced by an acyl group and exemplary acyl groups include a formyl group, an acetyl group, a trifluoroacetyl group, a propanoyl group, a n-butanoyl group, an i-butanoyl group, a pivaloyl group, a benzoyl group, an anisoyl group, and a nitrobenzoyl group.
Examples of the alkoxycarbonyl group as R1 and R2 include a methoxycarbonyl group, an ethoxycarbonyl group, a tert-butoxycarbonyl group, a benzyloxycarbonyl group, a methoxybenzylcarbonyl group and a nitrobenzylcarbonyl group.
Examples of the optionally substituted lower alkylsulfonyl group as R1 and R2 include a methanesulfonyl group and a trifluoromethanesulfonyl group.
Examples of the arylsulfonyl group as R1 and R2 include a benzensulfonyl group and a p-toluenesulofnyl group.
Examples of the substituent in the optionally substituted lower alkyl group as R3 and R4 include a halogen atom, a phenyl group, a hydroxyl group, a lower alkoxy group optionally substituted by a halogen atom or a phenyl group, and a lower alkylthio group optionally substituted by a halogen atom or a phenyl group. Preferred are halogen atoms, among which a fluorine atom is particularly preferred.
Examples of the optionally substituted lower alkyl group as R3 and R4 include a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a fluoroethyl group, a difluoroethyl group, a trifluoroethyl group, a tetrafluoroethyl group, a pentafluoroethyl group, a n-fluoropropyl group, a n-difluoropropyl group, a n-trifluoropropyl group, a n-tetrafluoropropyl group, a n-pentafluoropropyl group, a n-hexafluoropropyl group, a n-heptafluoropropyl group, a n-fluorobutyl group, a n-difluorobutyl group, a n-trifluorobutyl group, a n-tetrafluorobutyl group, a n-pentafluorobutyl group, a n-hexafluorobutyl group, a n-heptafluorobutyl group, a n-octafluorobutyl group, a n-nonafluorobutyl group, an i-fluoropropyl group, an i-difluoropropyl group, an i-trifluoropropyl group, an i-tetrafluoropropyl group, an i-pentafluoropropyl group, an i-hexafluoropropyl group, an i-heptafluoropropyl group, an i-fluorobutyl group, an i-difluorobutyl group, an i-trifluorobutyl group, an i-tetrafluorobutyl group, an i-pentafluorobutyl group, an i-hexafluorobutyl group, an i-heptafluorobutyl group., an i-octafluorobutyl group, an i-nonafluorobutyl group, a sec-fluorobutyl group, a sec-difluorobutyl group, a sec-trifluorobutyl group, a sec-tetrafluorobutyl group, a sec-pentafluorobutyl group, a sec-hexafluorobutyl group, a sec-heptafluorobutyl group, a sec-octafluorobutyl group, a sec-nonafluorobutyl group, a tert-fluorobutyl group, a tert-difluorobutyl group, a tert-trifluorobutyl group, a tert-tetrafluorobutyl group, a tert-pentafluorobutyl group, a tert-hexafluorobutyl group, a tert-heptafluorobutyl group, a tert-octafluorobutyl group, a tert-nonafluorobutyl group, a benzyl group, a methoxymethyl group, an ethoxymethyl group, a trifluoromethoxymethyl group, a benzyloxymethyl group, a methylthiomethyl group, an ethylthiomethyl group, and a methoxycarbonylmethyl group.
The lower fluoroalkyl group as R3 and R4 means a straight-chained or branched alkoxy group having 1-4 carbon atoms in which at least one hydrogen atom is replaced by a fluorine atom; examples include a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a fluoroethyl group, a difluoroethyl group, a trifluoroethyl group, a tetrafluoroethyl group, a pentafluoroethyl group, a n-fluoropropyl group, a n-difluoropropyl group, a n-trifluoropropyl group, a n-tetrafluoropropyl group, a n-pentafluoropropyl group, a n-hexafluoropropyl group, a n-heptafluoropropyl group, a n-fluorobutyl group, a n-difluorobutyl group, a n-trifluorobutyl group, a n-tetrafluorobutyl group, a n-pentafluorobutyl group, a n-hexafluorobutyl group, a n-heptafluorobutyl group, a n-octafluorobutyl group, a n-nonafluorobutyl group, an i-fluoropropyl group, an i-difluoropropyl group, an i-trifluoropropyl group, an i-tetrafluoropropyl group, an i-pentafluoropropyl group, an i-hexafluoropropyl group, an i-heptafluoropropyl group, an i-fluorobutyl group, an i-difluorobutyl group, an i-trifluorobutyl group, an i-tetrafluorobutyl grop up, an pentafluorobutyl group, an i-hexafluorobutyl group, an i-heptafluorobutyl group, an i-octafluorobutyl group, an i-nonafluorobutyl group, a sec-fluorobutyl group, a sec-difluorobutyl group, a sec-trifluorobutyl group, a sec-tetrafluorobutyl group, a sec-pentafluorobutyl group, a sec-hexafluorobutyl group, a sec-heptafluorobutyl group, a sec-octafluorobutyl group, a sec-nonafluorobutyl group, a tert-fluorobutyl group, a tert-difluorobutyl group, a tert-trifluorobutyl group, a tert-tetrafluorobutyl group, a tert-pentafluorobutyl group, a tert-hexafluorobutyl group, a tert-heptafluorobutyl group, a tert-octafluorobutyl group, and a tert-nonafluorobutyl group.
If R3 and R4 represent substituents which, when taken together with the carbon atom to which they are bound, form a polymethylene group, they are saturated spiro rings having 3-7 carbon atoms, as exemplified by a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring and a cycloheptane ring.
If R3 and R4 represent substituents which, when taken together with the carbon atom to which they are bound, form a heterocycle, they are saturated spiro heterocycles having 3-7 carbon atoms which contain a hetero atom, as exemplified by an azetidine ring, pyrrolidine ring, a piperidine ring, an oxetane ring, a tetrahydrofuran ring, a tetrahydropyran ring, a tetrahydrothiophene ring, and a tetrahydrothiopyran ring.
Preferred examples of X are an iodine atom, a bromine atom and a trifluoromethanesulfonyloxy group.
Preferred examples of Y include a fluorine atom, a chlorine atom, a methanesulfonyloxy group, a benzenesulfonyloxy group and a p-toluenesulfonyl group; among these, a fluorine atom and a chlorine atom are particularly preferred.
While X and Y may be the same or different, they are preferably different.
There are two preferred combinations of X and Y; in one combination, X is a bromine atom and Y is a chlorine atom and in the other combination, X is an iodine atom and Y is a chlorine atom.
Preferred examples of R1 are a lower perfluoroalkyl group, a nitro group and a cyano group; among these, lower perfluoroalkyl groups are preferred, with a trifluoromethyl group and a pentafluoroethyl group being particularly preferred.
The preferred position of substitution by R1 is in 6-position on the benzopyran ring.
The preferred example of R2 is a hydrogen atom.
It is preferred that R3 and R4 are the same; more preferably, they both are a lower alkyl group or a lower fluoroalkyl group; most preferably, they both are a fluoromethyl group.
Examples of the optionally substituted lower alkyl group as R5 and R6 include a methyl group, a benzyl group, a cyclopropylmethyl group, an ethyl group, a 2-cyanoethyl group, a 2-fluoroethyl group and a n-propyl group.
Preferably, R5 is a hydrogen. atom and R6 is an optionally substituted lower alkyl group; more preferably, R5 is a hydrogen atom and R6 is a lower alkyl group optionally having a cyano group; most preferably, R5 is a hydrogen atom and R6 is a 2-cyanoethyl group or a 2-cyanomethyl group.
A compound represented by the general formula (II) (where X and Y have the same meanings as defined above; R1 and R2 have the same meanings as defined above) is reacted with an olefin represented by the general formula (III) (where R3 and R4 have the same meanings as defined above) in a suitable solvent in the presence of a suitable metal catalyst, a suitable base and a suitable quaternary ammonium salt under an inert atomosphere at a suitable temperature to give a compound represented by the general formula (IV) (where Y, R1, R2, R3 and R4 have the same meanings as defined above). The suitable metal catalyst as used herein means a palladium or a nickel catalyst and examples include palladium acetate, palladium chloride, palladium carbon, bis(triphenylphosphine)palladium acetate, bis(triphenylphosphine)palladium chloride, tris(dibenzylideneacetone)dipalladium, bis(dibenzylideneacetone)palladium, tetrakis(triphenylphosphine)palladium, [1,1xe2x80x2-bis(diphenylphosphino)ferrocene]palladium chloride, allyl palladium chloride, bis(acetonitrile)palladium chloride, nickel acetate, nickel chloride, bis(1,5-octadiene)nickel, bis(triphenylphosphine)nickel chloride, dicyclopentadienyl nickel, and nickel acetoacetonate; among these, palladium acetate is preferred. Examples of the suitable base include diethylamine, triethylamine, diisopropylethylamine, sodium hydrogencarbonate, sodium carbonate, potassium hydrogencarbonate, potassium carbonate, dipotassium hydrogenphosphate, potassium phosphate, sodium hydroxide and potassium hydroxide; among these, potassium carbonate is preferred. Examples of the suitable quaternary ammonium salt include tetrabutylammonium iodide, tetrabutylammonium bromide, tetrabutylammonium chloride, benzyltriethylammonium chloride and benzyltrimethylammonium hydroxide; among these, tetrabutylammonium bromide is preferred. Examples of the suitable solvent include N,N-dimethylformamide, N,N-dimethylacetamide, toluene, xylene, acetonitrile and dioxane; among these, N,N-dimethylacetamide is preferred. An example of the suitable temperature is between room temperature and 130xc2x0 C., preferably between 75xc2x0 C. and 85xc2x0 C. Examples of the inert gas are nitrogen and argon.
The resulting compound of the general formula (IV) is reacted with a halogenating agent (e.g. bromine) in a suitable solvent at a suitable temperature to give a compound represented by the general formula (V) (where Y, R1, R2, R3, R4 and Hal have the same meanings as defined above). Examples of the suitable solvent include dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, diethyl ether, tert-butyl methyl ether, tert-butyl alcohol, tert-amyl alcohol, 3-methyl-3-pentanol and 3-ethyl-3-pentanol; among these, tert-amyl alcohol is preferred. An example of the suitable temperature is between xe2x88x9278xc2x0 C. and 80xc2x0 C., preferably between xe2x88x9215xc2x0 C. and xe2x88x925xc2x0 C.
The resulting compound of the general formula (V) is reacted with a suitable base in a suitable solvent at a suitable temperature to give a compound represented by the general formula (VI) (where Y, R1, R2, R3, R4 and Hal have the same meanings as defined above). Examples of the suitable base include diethylamine, triethylamine, diisopropylethylamine, sodium hydride, potassium hydride, potassium tert-butoxide, sodium methoxide, sodium ethoxide, sodium bis(trimethylsilyl)amide, potassium bis(trimethylsilyl)amide, soium hydrogencarbonate, sodium carbonate, potassium hydrogencarbonate, potassium carbonate, dipotassium hydrogenphosphate, potassium phosphate, sodium hydroxide and potassium hydroxide; among these, sodium hydride and potassium carbonate are preferred. Examples of the suitable solvent include dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, tert-butyl alcohol, tert-amyl alcohol, 3-methyl-3-pentanol, 3-ethyl-3-pentanol, tetrahydrofuran, dioxane, N,N-dimethylformamide, N,N-dimethylacetamide, toluene and xylene; among these, toluene and tert-amyl alcohol are preferred. An example of the suitable temperature is between xe2x88x9278xc2x0 C. and 80xc2x0 C., preferably between 30xc2x0 C. and 60xc2x0 C.
The resulting compound of the general formula (VI) is reacted with a suitable base in asuitable solvent at a suitable temperature to give a compound represented by the general formula (I) (where R1, R2, R3, R4 and Hal have the same meanings as defined above). Examples of the suitable base include sodium hydride, potassium hydride, potassium tert-butoxide, sodium bis(trimethylsilyl)amide and potassium bis(trimethylsilyl)amide; among these, sodium hydride and potassium bis(trimethylsilyl)amide are preferred. Examples of the preferred suitable solvent include tetrahydrofuran, dioxane, N,N-dimethylformamide, N,N-dimethylacetamide, toluene and xylene; among these, toluene and tetrahydrofuran are preferred. An example of the suitable temperature is between xe2x88x9278xc2x0 C. and 80xc2x0 C., preferably between xe2x88x9215xc2x0 C. and xe2x88x925xc2x0 C.
The compound of the general formula (I) can also be prepared by the following scheme. Namely, a compound represented by the general formula (II) (where X, Y, R1 and R2 have the same meanings as defined above) is reacted with acetylene represented by the general formula (VII) (where R3 and R4 have the same meanings as defined above) in a suitable solvent in the presence of a suitable metal catalyst, a suitable ligand, a suitable copper salt and a suitable base in an inert atmosphere at a suitable temperature to give a compound represented by the general formula ((VIII) (where Y, R1, R2, R3 and R4 have the same meanings as defined above). The suitable metal catalyst as used herein means a palladium or a nickel catalyst and examples include palladium acetate, palladium chloride, palladium carbon, nickel acetate and nickel chloride; alternatively, the metal catalyst is a complex with a ligand, as exemplified by bis(triphenylphosphine)palladium acetate, bis(triphenylphosphine)palladium chloride, tris(dibenzylideneacetone)dipalladium, bis(dibenzylideneacetone)palladium, tetrakis(triphenylphosphine)palladium, [1,1xe2x80x2-bis(diphenylphosphino)ferrocene]palladium chloride, allyl palladium chloride, bis(acetonitrile)palladium chloride, bis(1,5-octadiene)nickel, bis(triphenylphosphine)nickel chloride, dicyclopentadienyl nickel and nickel acetoacetonate. Examples of the suitable ligand include triphenylphosphine, tris(o-tolyl)phosphine, 1,1xe2x80x2-bis(diphenylphosphino)ferrocene and dibenzylidene acetone; among these bis(triphenylphosphine)palladium chloride is preferred. Examples of the suitable copper salt include a copper(0) powder, cuprous chloride, cuprous bromide, cuprous iodide and cuprous acetate; among these, cuprous iodide is preferred. Examples of the suitable base include diethylamine, triethylamine, diisopropylethylamine, sodium hydrogencarbonate, sodium carbonate, potassium hydrogencarbonate, potassium carbonate, dipotassium hydrogenphosphate, potassium phosphate, sodium hydroxide and potassium hydroxide; among these, triethylamine being preferred. Examples of the suitable solvent include triethylamine, N,N-dimethylformamide, N,N-dimethylacetamide, toluene, xylene, acetonitrile and dioxane; among these, N,N-dimethylformamide is preferred. An example of the preferred temperature is between room temperature and 130xc2x0 C., preferably between 75xc2x0 C. and 85xc2x0 C. Examples of the inert gas include nitrogen and argon.
The resulting compound of the general formula (VIII) is subjected to reaction under a hydrogen atmosphere in the presence of a suitable catalyst and a suitable solvent at a suitable temperature to give a compound represented by the general formula (IX) (where Y, R1, R2, R3 and R4 have the same meanings as defined above). Examples of the suitable catalyst include a Lindlar catalyst, developed Raney nickel, barium carbonate-palladium and barium sulfate-palladium, with 5% palladium-bariuxm carbonate being preferred. Examples of the suitable solvent include methanol, ethanol, ethyl acetate and methanol-pyridine, with 5% pyridine-methanol and ethyl acetate being preferred. An example of the suitable temperature is between room temperature and 60xc2x0 C. preferably room temperature.
The resulting compound of the general formula (IX) is reacted with a suitable base in a suitable solvent at a suitable temperature to give a compound represented by the general formula (X) (where R1, R2, R3 and R4 have the same meanings as defined above). Examples of the suitable base include sodium hydride, potassium hydride, potassium tert-butoxide, sodium-bis(trimethylsilyl)amide and potassium bis(trimethylsilyl)amide, with potassium tert-butoxide being preferred. Examples of the suitable solvent include tetrahydrofuran, dioxane, N,N-dimethylformamide, N,N-dimethylacetamide, 1,3-dimethylimidazolidin-2-one, N-methylpyrrolidone, sulfolane, toluene and xylene, with N,N-dimethylformamide being preferred. An example of the suitable temperature is between xe2x88x9278xc2x0 C. and 80xc2x0 C., preferably between 55xc2x0 C. and 65xc2x0 C.
The resulting compound of the general formula (X) is reacted with a halogenating agent (e.g. bromine) in a suitable solvent at a suitable temperature to give a compound represented by the general formula (XI) (where R1, R2, R3, R4 and Hal have the same meanings as defined above). Examples of the suitable solvent include dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, diethyl ether and tert-butyl methyl ether, with chloroform and tert-butyl methyl ether being preferred. An example of the preferred temperature is between xe2x88x9278xc2x0 C. and room temperature, preferably between xe2x88x9210xc2x0 C. and room temperature.
The resulting compound of the general formula (XI) is reacted with a suitable base in a suitable solvent at a suitable temperature to give a compound represented by the general formula (I) (where R1, R2, R3, R4 and Hal have the same meanings as defined above). Examples of the suitable base include sodium hydride, potassium hydride, potassium tert-butoxide, sodium hydrogencarbonate, sodium carbonate, potassium hydrogencarbonate, potassium carbonate, dipotassium hydrogenphosphate, potassium phosphate, sodium hydroxide and potassium hydroxide, with potassium hydroxide being preferred. Examples of the suitable solvent include water, tetrahydrofuran, dioxane, N,N-dimethylformamide, N,N-dimethylacetamide, toluene, xylene, methanol and ethanol, with water-dioxane and ethanol being preferred. An example of the suitable temperature is between xe2x88x9278xc2x0 C. and 80xc2x0 C., preferably between room temperature and 80xc2x0 C.
The resulting compound of the general formula (I) is converted to a compound of the general formula (G-VI) by a method that involves a carbon monoxide inserting cross-coupling reaction as a key reaction that uses a metal as a catalyst. To be specific, the compound of the general formula (I) (where R1, R2, R3, R4 and Hal have the same meanings as defined above) is subjected to a cross-coupling reaction with a compound of the general formula (G-III)
HNR5R6xe2x80x83xe2x80x83(G-III)
(where R5 and R6 have the same meanings as defined above) under a carbon monoxide gas at atmospheric or superatmospheric pressure from a CO gas container, preferably at atmospheric pressure, at a reaction temperature between xe2x88x9278xc2x0 C. and 150xc2x0 C., preferably between room temperature and 130xc2x0 C., for a reaction time of from 1 hour to 3 days, preferably from 3 hours to 1 day, in the presence of a zero-valence or divalent metal catalyst such as palladium, nickel, copper, zinc, tin or magnesium, preferably, 1-5 mol % of zero-valence or divalent palladium such as bis(triphenylphosphine)palladium acetate, palladium acetate and triphenylphosphine, bis(triphenylphosphine)palladium chloride, [1,1xe2x80x2-bis(diphenylphosphino)ferrocene]palladium chloride dichloromethane adduct, tetrakis(triphenylphosphine)palladium, tris(dibenzylideneacetone)dipalladium chloroform adduct and triphenylphosphine, and tris(dibenzylideneacetone)dipalladium chloroform adduct in a solvent such as N,N-dimethylformamide, tetrahydrofuran, dioxane, ether, acetonitrile, toluene, benzene or water, preferably N,N-dimethylformamide, thereby giving a 4-substituted benzopyran derivative represented by the general formula (G-VI) (where R1, R2, R3, R4, R5 and R6 have the same meanings as defined above).
B. Schemes (3) and (4):
Speaking of the process according to schemes (3) and (4), the preferred substituents in the 4-substituted benzopyran derivatives of the general formula (G-VI) are exemplified by the following.
Preferably, R1 and R2 which may be the same or different represent a hydrogen atom, an optionally substituted lower alkyl group, an optionally substituted lower alkoxy group, an optionally substituted lower alkoxycarbonyl group, an optionally substituted lower alkylsulfonyl group, an optionally substituted arylsulfonyl group, a halogen atom, a nitro group, a cyano group or NYaYb (where Ya and Yb which may be the same or different each represent a hydrogen atom, an optionally substituted lower alkyl group, an optionally substituted lower alkoxycarbonyl group, an acyl group, an optionally substituted lower alkylsulfonyl group or an optionally substituted arylsulfonyl group or, when taken together with the nitrogen atom to which they are bound, may form a 3- to 8-membered ring).
Preferably, R3 and R4 which may be the same or different represent a hydrogen atom or an optionally substituted xcex1-haloalkyl group, provided that they are not both a hydrogen atom.
Preferably, R5 and R6 which may be the same or different represent a hydrogen atom or an optionally substituted lower alkyl group.
In schemes (3) and (4), unless otherwise noted, the following definitions hold:
the lower alkyl group means a straight-chained alkyl group having 1-6 carbon atoms or a branched or cyclic alkyl group having 3-8 carbon atoms; examples include a methyl group, an ethyl group, a n-propyl group, a n-butyl group, a n-pentyl group, a n-hexyl group, an i-propyl group, an i-butyl group, a sec-butyl group, a tert-butyl group, an i-pentyl group, a neopentyl group, a tert-pentyl group, an i-hexyl group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group and a cyclooctyl group;
the halogen atom means a fluorine atom, a chlorine atom, a bromine atom or an iodine atom;
the lower alkoxy group means a straight-chained alkoxy group having 1-6 carbon atoms or a branched or cyclic alkoxy group having 3-8 carbon atoms; examples include a methoxy group, an ethoxy group, a n-propoxy group, a n-butoxy group, a n-pentoxy group, a n-hexoxy group, an i-propoxy group, an i-butoxy group, a sec-butoxy group, a tert-butoxy group, an i-pentoxy group, a neopentoxy group, a tert-pentoxy group, an i-hexoxy group, a cyclopropoxy group, a cyclobutoxy group, a cyclopentoxy group, a cyclohexoxy group, a cycloheptoxy group and a cyclooctoxy group.
the lower alkoxycarbonyl group means an alkoxycarbonyl group whose alkyl portion is a straight-chained alkyl group having 1-6 carbon atoms or an alkoxycarbonyl group whose alkyl portion is a branched or cyclic alkyl group having 3-8 carbon atoms, and examples include a methoxycarbonyl group, an ethoxycarbonyl group, a n-propoxycarbonyl group, a n-butoxycarbonyl group, a n-pentoxycarbonyl group, a n-hexoxycarbonyl group, an i-propoxycarbonyl group, an i-butoxycarbonyl group, a sec-butoxycarbonyl group, a tert-butoxycarbonyl group, an i-pentoxycarbonyl group, a neopentoxycarbonyl group, a tert-pentoxycarbonyl group, an i-hexoxycarbonyl group, a cyclopropoxycarbonyl group, a cyclobutoxycarbonyl group, a cyclopentoxycarbonyl group, a cyclohexoxycarbonyl group, a cycloheptoxycarbonyl group and a cyclooctoxycarbonyl group;
the lower alkylsulfonyl group means an alkylsulfonyl group having 1-8 carbon atoms whose alkyl portion is a straight-chained alkyl group or an alkylsulfonyl group having 3-8 carbon atoms whose alkyl portion is a branched or cyclic alkyl group, and examples include a methylsulfonyl group, an ethylsulfonyl group, a propylsulfonyl group, an isopropylsulfonyl group, a butylsulfonyl group and an isobutylsulfonyl group.
the arylsulfonyl group means an aromatic sulfonyl group and examples include a phenylsulfonyl group, a p-tolylsulfonyl group, a p-chlorophenylsulfonyl group, a 2-furylsulfonyl group, a 3-furylsulfonyl group, a 2-thienylsulfonyl group, a 3-thienylsulfonyl group, a 2-pyridylsulfonyl group, a 3-pyridylsulfonyl group and a 4-pyridylsulfonyl group.
Ya and Yb in NYaYb which may be the same or different each represent a hydrogen atom, an optionally substituted lower alkyl group, an optionally substituted lower alkoxycarbonyl group, an acyl group, an optionally substituted lower alkylsulfonyl group or an optionally substituted arylsulfonyl group or, when taken together with the nitrogen atom to which they are bound, may form a 3- to 8-membered ring.
The acyl group as used herein means a formyl group or an alkylcarbonyl group having 1-8 carbon atoms whose alkyl portion is an optionally substituted straight-chained alkyl group, an alkylcarbonyl group having 3-8 carbon atoms whose alkyl portion is an optionally substituted branched or cyclic alkyl group, or an arylcarbonyl group, and examples include a formyl group, an acetyl group, a trifluoroacetyl group, a propionyl group, a butyryl group, a valeryl group, an isobutyryl group, an isovaleryl group, a pivaloyl group, a benzoyl group, a phthaloyl group and a toluoyl group.
When either one of Ya and Yb is a hydrogen atom and the other is an acyl group, NYaYb represents an acylamino group.
When both Ya and Yb are a hydrogen atom, NYaYb represents an amino group.
If R1, R2, R3, R4, R5 or R6 represents an optionally substituted lower alkyl group, an optionally substituted lower alkoxy group, an optionally substituted lower alkoxycarbonyl group or an optionally substituted lower alkylsulfonyl group, the optionally present substituent may be exemplified by a halogen atom, a phenyl group, a hydroxy group, a nitro group, a cyano group, a cyclic alkyl group having 3-8 carbon atoms, a lower alkoxy group optionally substituted by a halogen atom or a phenyl group, a lower alkoxycarbonyl group, a carboxyl group and NYcYd; Yc and Yd which may be the same or different each represent a hydrogen atom, a lower alkyl group, a lower alkoxycarbonyl group, an acyl group, a lower alkylsulfonyl group or an optionally substituted arylsulfonyl group or, when taken together with the nitrogen atom to which they are bonded, may form a 3- to 8-numbered ring.
When taken together with the nitrogen atom to which they are bound, Ya and Yb, Yc and Yd, or Ye and Yf may form a 3- to 8-membered ring and the ring has 2-7 carbon atoms, with any carbon atom on the ring being optionally replaced by a nitrogen atom, an oxygen atom or a sulfur atom. Specific examples include an aziridine ring, an azetidine ring, a pyrrole ring, a pyrrolidine ring, a pyridine ring, a 3,4-dihydro-2H-azepine ring, a 3,4,5,6-tetrahydro-2H-azepine ring, an azocine ring, a 5,6-dihydro-azocine ring, a 5,6,7,8-tetrahydroazocine ring, an oxazoline ring, an isoxazoline ring, a thioxazoline ring, a piperazine ring, a morpholine ring and a thiomorpholine ring.
The xcex1-haloalkyl group as R3 and R4 means a straight-chained alkyl group having 1-6 carbon atoms or a branched or cyclic alkyl group having 3-8 carbon atoms that have 1-3 halogen atoms in 1-position and which may further possess a substituent, and examples include a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a 1-fluoroethyl group, a 1,1-difluoroethyl group, a 1-fluoropropyl group, a 1,1-difluoropropyl group, a 1-fluorocyclopropyl group, a 1-fluorobutyl group, a 1,1-difluorobutyl group, a chloromethyl group, a dichloromethyl group, a trichloromethyl group, a. -chloroethyl group, a 1,1-dichloroethyl group, a 1-chloropropyl group, a 1,1-chloropropyl group, a 1-chlorocyclopropyl group, a 1-chlorobutyl group, a 1,1-dichlorobutyl group, a bromomethyl group, a dibromomethyl group, a tribromomethyl group, a 1-bromoethyl group, a 1,1-dibromoethyl group, a 1-bromopropyl group, a 1,1-dibromopropyl group, a 1-bromocyclopropyl group, a 1-bromobutyl group, a 1,1-dibromobutyl group, an iodomethyl group, a diodomethyl group, a triiodomethyl group, a 1-iodoethyl group, a 1, i-diiodoethyl group, a 1-iodopropyl group, a 1,1-diiodopropyl group, a 1-iodocyclopropyl group, a 1-iodobutyl group and a 1,1-dijodobutyl group.
If R1 or R2 represents an optionally substituted arylsulfonyl group or an optionally substituted aryl group, the optionally present substituent may be exemplified by a halogen atom, a phenyl group, a hydroxy group, a nitro group, a cyano group, a straight-chained alkyl group having 1-6 carbon atoms, a branched or cyclic alkyl group having 3-8 carbon atoms, a lower alkoxy group optionally substituted by a halogen atom or a phenyl group, a lower alkylthio group optionally substituted by a halogen atom or a phenyl group, a lower alkoxycarbonyl group, a carboxyl group and NYeYf; Ye and Yf which may be the same or different each represent a hydrogen atom, an optionally substituted lower alkyl group, an optionally substituted lower alkoxycarbonyl group, an acyl group, an optionally substituted lower alkylsulfonyl group or an arylsulfonyl group or, when taken together, may form a 3- to 8-numbered ring.
Examples of the optionally substituted lower alkyl group as R1 and R2 include a methyl group, a fluoromethyl group, a trifluoromethyl group, a pentafluoroethyl group, a benzyl group, a nitromethyl group, a cyclopropylmethyl group, a methoxymethyl group, an ethoxymethyl group, a benzyloxymethyl group, a methylthiomethyl group, an ethylthiomethyl group, a methoxycarbonylmethyl group, a dimethylaminomethyl group, an ethyl group, a 2-fluoroethyl group, a n-propyl group, an i-propyl group, a 1-methylthiopropyl group and a n-butyl group.
Examples of the optionally substituted lower alkyl group as R5, R6 and R6a include a methyl group, a benzyl group, a cyclopropylmethyl group, an ethyl group, a 2-cyanoethyl group, a 2-fluoroethyl group and a n-propyl group.
Speaking of R5 and R6, a preferred case is where R5 is a hydrogen atom and R6 is an optionally substituted lower alkyl group; a more preferred case is where R5 is a hydrogen atom and R6 is a lower alkyl group optionally having a cyano group, and a particularly preferred case is where R5 is a hydrogen atom and R6 is a 2-cyanoethyl group or a 2-cyanomethyl group.
A preferred example of R6a is a lower alkyl group optionally having a cyano group; more preferred examples are a 2-cyanoethyl group and a 2-cyanomethyl group, with a 2-cyanoethyl group being particularly preferred.
Examples of the optionally substituted lower alkoxy group as R1 and R2 include a methoxy group, a trifluoromethoxy group, a benzyloxy group, a cyclopropylmethoxy group, an ethoxy group and a n-propoxy group.
Examples of the optionally substituted lower alkoxycarbonyl group as R1 and R2 include a methoxycarbonyl group, a trifluoromethoxycarbonyl group, a benzyloxycarbonyl group, a cyclopropylmethoxycarbonyl group, an ethoxycarbonyl group, a n-propoxycarbonyl group and a tert-butoxycarbonyl group.
The preferred position of substitution by R1 is in 6-position on the benzopyran ring. Preferred examples of R1 include an optionally substituted lower alkyl group, an optionally substituted alkylsulfonyl group, an optionally substituted arylsulfonyl group, a nitro group and a cyano group; among these, lower alkyl groups having a fluorine atom as a substituent are preferred, with a 6-trifluoromethyl group and a 6-pentafluoroethyl group being particularly preferred.
The preferred example of R2 is a hydrogen atom.
Speaking of R3 and R4, they are preferably the same; more preferably, they both are an optionally substituted xcex1-haloalkyl group; most preferably, they both are a fluoromethyl group.
Examples of the optionally substituted alkyl group as R7 include a methyl group, an ethyl group and a propyl group. Examples of the optionally substituted aryl group as R7 include a phenyl group, a p-tolyl group and a p-chlorophenyl group; among these, a p-tolyl group and a methyl group are preferred, with a p-tolyl group being particularly preferred.
Examples of the above-mentioned NYaYb, NYcYd and NYeYf include an amino group, a methylamino group, a benzylamino group, an ethylamino group, a dimethylamino group, an ethylmethylamino group, a pyrrolidinyl group, a piperidino group, a morpholino group, an acetamido group, a benzamido group, an N-methylacetamido group, a tert-butoxycarbonylamino group, an N-methyl-tert-butoxycarbonylamino group, a methylsulfonylamino group, an ethylsulfonylamino group, a propylsulfonylamino group, an isopropylsulfonylamino group, a butylsulfonylamino group, an isobutylsulfonylamino group, a phenylsulfonylamino group, a p-tolylsulfonylamino group and a p-chlorophenylsulfonylamino group.
For synthesis of the compound represented by the general formula (G-II), the compound represented by the general formula (G-I) is used as an intermediate and this compound, being undocumented and novel, constituents the present invention. To give the compound of the general formula (G-I), a sulfonate ester represented by the general formula (C-IV) (where R7, R3 and R4 have the same meanings as defined above) may be reacted with a phenol represented by the general formula (C-V) (where R1 and R2 have the same meanings as defined above) in an inert solvent such as acetonitrile that does not affect the reaction, in the presence of a suitable base and a catalytic amount of a suitable copper salt at a temperature between xe2x88x9278xc2x0 C. and room temperature, preferably between 0xc2x0 C. and room temperature. Examples of the suitable base that can be used in the reaction include organic strong bases such as 1,8-diazabicyclo(5.4.0)-7-undecene and 1,5-diazabicyclo(4.3.0)-5-nonene, and tertiary amines such as triethylamine, tributylamine and N,N-diisopropylethylamine, with N,N-diisopropylethylamine being preferred. Exampples of the suitable copper base that can be used in the reaction include cuprous salts such as copper(I) acetate, copper(I) trifluoroacetate, cuprous chloride, cuprous bromide, cuprous iodide and cuprous cyanide, and cupric salts such as cupric chloride and cupric bromide, with cupric chloride and cupric bromide being preferred.
For synthesis of the compound of the general formula (G-I), the compound represented by the general formula (C-IV) is used as an intermediate and this compound, being undocumented and novel, constitutes the present invention. To prepare the compound of the general formula (C-IV), an alcohol represented by the general formula (C-I) (where R3 and R4 have the same meanings as defined above) may be reacted with a compound of the general formula (C-II) or (C-III)
R7SO2Clxe2x80x83xe2x80x83(C-II)
(R7SO2)2Oxe2x80x83xe2x80x83(C-III)
(where R7 represents an optionally substituted alkyl group or an optionally substituted aryl group) either after reacting the alcohol with a suitable base in a suitable solvent to be converted to an alkoxide or directly in a suitable solvent in the presence of a suitable base at a temperature between xe2x88x9278xc2x0 C. and room temperature, preferably between 0xc2x0 C. and room temperature. In this reaction, a suitable catalyst such as N,N-dimethylaminopyridine may be used. The suitable solvent that can be used in this reaction is an inert solvent that does not affect the reaction, as exemplified by diethyl ether, diisopropyl ether, tert-butyl methyl ether, tetrahydrofuran, dioxane, diglyme, acetone, N,N-dimethylformamide, N,N-dimethylacetamide and dimethyl sulfide, with tetrahydrofuran and tert-butyl methyl ether being preferred. Examples of the suitable base that can be used in the reaction include alkali metal hydrides such as potassium hydride, sodium hydride and lithium hydride, or carbonates such as potassium carbonate and sodium carbonate, bicarbonates such as potassium hydrogencarbonate and sodium hydrogencarbonate, organic strong bases such as 1,8-diazabicyclo(5.4.0)-7-undecene and 1,5-diazabicyclo(4.3.0)-5-nonene, tertiary amines such as triethylamine, tributylamine and N,N-diisopropylethylamine; among these, sodium hydride and triethylamine are preferred.
The compound of the invention which is represented by the general formula (G-VI) may be synthesized by the following procedure:
a compound represented by the general formula (G-I) (where R1, R2, R3 and R4 have the same meanings as defined above) is reacted in an inert solvent such as hexane, toluene, diethyl ether, diisopropyl ether, tert-butyl methyl ether, tetrahydrofuran, dioxane or tert-butanol, preferably in tert-butyl methyl ether, tetrahydrofuran or diethyl ether, at a temperature between xe2x88x9278xc2x0 C. and the boiling point of the reaction mixture, preferably between xe2x88x9240xc2x0 C. and room temperature, with an alkali metal such as lithium, sodium or potassium, alkyllithium such as methyllithium, ethyllithium, n-propyllithium, i-propyllithium, n-butyllithium, sec-butyllithium or tert-butyllithium, or a Grignard reagent such as methylmagnesium chloride, methylmagnesium bromide, methylmagnesium iodide, ethylmagnesium chloride, ethylmagnesium bromide, ethylmagnesium iodide, n-propylmagnesium chloride, n-propylmagnesium bromide, n-propylmagnesium iodide, i-propylmagnesium chloride, i-propylmagnesium bromide, i-propylmagnesium iodide, n-butylmagnesium chloride, n-butylmagnesium bromide, n-butylmagnesium iodide, sec-butylmagnesium chloride, sec-butylmagnesium bromide, sec-butylmagnesium iodide, tert-butylmagnesium chloride, tert-butylmagnesium bromide or tert-butylmagnesium iodide, or a reagent selected from among lithium hydride, sodium hydride, potassium hydride, tert-butoxypotassium, lithium amide, sodium amide, potassium amide, lithium diisopropylamide, sodium diisopropylamide, potassium diisopropylamide, sodium bis(trimethylsilyl)amide and potassium bis(trimethylsilyl)amide, preferably reacted with n-butyllithium or tert-butylmagnesium chloride; then, reaction with carbon dioxide follows to give a compound represented by the general formula (G-II) (where R1, R2, R3 and R4 have the same meanings as defined above); subsequently, the compound represented by the general formula (G-VI) (where R1, R2, R3, R4, R5 and R6 have the same meanings as defined above) is obtained by performing amidation reaction on the compound of the general formula (G-II) in the usual manner. Amidation reaction typically involves reaction with a suitable condensing agent and an amine of the general formula (G-III)
R5R6NHxe2x80x83xe2x80x83(G-III)
xe2x80x83(where R5 and R6 which may be the same or different represent a hydrogen atom or an optionally substituted lower alkyl group) in an inert solvent in the presence or absence of an organic base or an inorganic base (preferably, in their absence).
The condensing agent is a reagent selected from among commonly used condensing agents such as hydrochlorides of dicyclohexylcarbodiimide, diisopropylcarbodiimide and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, and methyl chloroformate, ethyl chloroformate and isopropyl chloroformate, with a hydrochloride of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and ethyl chloroformate being preferred.
Exemplary organic bases include pyridine and triethylamine. Exemplary inorganic bases include sodium hydroxide, sodium alkoxide, potassium alkoxide, alkyllithium, potassium carbonate., sodium carbonate and potassium hydroxide.
Useful reaction solvents are inert solvents such as toluene, diethyl ether, diisopropyl ether, tert-butyl methyl ether, tetrahydrofuran, dioxane, dichloromethane, dichloroethane, chloroform and ethyl acetate, or mixtures of solvents selected from among these solvents; preferably, tert-butyl methyl ether, ethyl acetate and dichloromethane are used. The reaction temperature is between xe2x88x9278xc2x0 C. and the boiling point of the reaction mixture, preferably between xe2x88x9240xc2x0 C. and room temperature.
The compound which is represented by the general formula (G-V) (where R1, R2, R3, R4, R5 and R6 have the same meanings as defined above) can also be obtained by the following procedure:
a compound represented by the general formula (G-I) (where R1, R2, R3 and R4 have the same meanings as defined above) is reacted in an inert solvent such as hexane, toluene, diethyl ether, diisopropyl ether, tert-butyl methyl ether, tetrahydrofuran or dioxane, preferably in tert-butyl methyl ether, tetrahydrofuran or diethyl ether, at a temperature between xe2x88x9278xc2x0 C. and the boiling point of the reaction mixture, preferably between xe2x88x9240xc2x0 C. and room temperature, with an alkali metal such as lithium, sodium or potassium, alkyllithium such as methyllithium, ethyllithium, n-propyllithium, i-propyllithium, n-butyllithium, sec-butyllithium or tert-butyllithium, or a Grignard reagent such as methylmagnesium chloride, methylmagnesium bromide, methylmagnesium iodide, ethylmagnesium chloride, ethylmagnesium bromide, ethylmagnesium iodide, n-propylmagnesium chloride, n-propylmagnesium bromide, n-propylmagnesium iodide, i-propylmagnesium chloride, i-propylmagnesium bromide, i-propylmagnesium iodide, n-butylmagnesium chloride, n-butylmagnesium bromide, n-butylmagnesium iodide, sec-butylmagnesium chloride, sec-butylmagnesium bromide, sec-butylmagnesium iodide, tert-butylmagnesium chloride, tert-butylmagnesium bromide or tert-butylmagnesium iodide, or a reagent selected from among lithium hydride, sodium hydride, potassium hydride, tert-butoxypotassium, lithium amide, sodium amide, potassium amide, lithium diisopropylamide, sodium diusopropylamide, potassium diisopropylamide, sodium bis(trimethylsilyl)amide and potassium bis(trimethylsilyl)amide, preferably reacted with n-butyllithium or tert-butylmagnesium chloride; subsequently, reaction is performed with a compound represented by the general formula (G-IVa) (where R5 and R6 which may be the same or different represent a hydrogen atom or an optionally substituted lower alkyl group) or a compound represented by the general formula (G-IVb)
R6aNCOxe2x80x83xe2x80x83(G-IVb)
xe2x80x83(where R6a represents an optionally substituted lower alkyl group).
If the resulting compound of the general formula (G-V) is heated in an inert solvent such as a saturated hydrocarbon (e.g. decane, undecane, dodecane, tridecane, tetradecane, cis-decalin or trans,-decalin), an aromatic hydrocarbon (e.g. toluene, xylene, dichlorobenzene, tetralin or biphenyl), an ether-containing hydrocarbon (e.g. diglyme, triglyme, tetraglyme or diphenyl ether), a sulfolane-containing hyrocarbon (e.g. sulfolane) or a mixture thereof, preferably, undecane, dodecane, cis-decalin, trans-decalin, tetralin or a mixture thereof, at 100-300xc2x0 C., preferably at 160-250xc2x0 C., there is produced a 4-substituted benzopyran derivative represented by the general formula (G-VI) (where R1, R2, R3, R4, R5 and R6 have the same meanings as defined above). During this thermal cyclization reaction, a benzofuran derivative represented by the general formula (G-VII) forms as a by-product. It was found that the yield ratio between the end product 4-substituted benzopyran derivative and the by-product benzofuran derivative depends largely upon the reaction solvent and the reaction temperature; when diethylaniline, a common conventional solvent for the thermal cyclization reaction, was used as the reaction solvent, benzopyran derivatives were not obtained at all but only benzofuran derivatives occurred.
The compound of the general formula (G-II) can also be obtained in salt form; specific examples of its salt include a lithium salt, a sodium salt, a potassium salt and a magnesium salt, with a sodium salt and a potassium salt being preferred.
If a compound of the general, formula (G-IVb) is used, R5 in the compound of the general formula (G-VI) is a hydrogen atom.
C. Schemes (5) and (6):
For schemes (5) and (6), preferred examples of R1 and R2 which may be the same or different include a hydrogen atom, an optionally substituted lower alkyl group, a halogen atom, an optionally substituted lower alkoxy group, NYaYb (where Ya and Yb which may be the same or different each represent a hydrogen atom, an optionally substituted lower alkyl group, an optionally substituted lower alkoxycarbonyl group, an acyl group, an optionally substituted lower alkylsulfonyl group or an optionally substituted arylsulfonyl group or, when taken together with the nitrogen atom to which they are bound, may form a 3- to 8-membered ring), a nitro group, a cyano group, an optionally substituted lower alkoxycarbonyl group, an optionally substituted lower alkylsulfonyl group, and an optionally substituted arylsulfonyl group. These groups correspond to R1g and R2g as defined in the general formula (Iz).
Preferably, R5 and R6 which may be the same or different are a hydrogen atom or an optionally substituted lower alkyl group.
In schemes (5) and (6), unless otherwise noted, the following definitions hold:
the lower alkyl group means a straight-chained alkyl group having 1-6 carbon atoms or a branched or cyclic alkyl group having 3-8 carbon atoms; examples include a methyl group, an ethyl group, a n-prbpyl group, a n-butyl group, a n-pentyl group, a n-hexyl group, an i-propyl group, an i-butyl group, a sec-butyl group, a tert-butyl group, an i-pentyl group, a neopentyl group, a tert-pentyl group, an i-hexyl group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group and a cyclooctyl group;
the halogen atom means a fluorine atom, a chlorine atom, a bromine atom or an iodine atom;
the lower alkoxy group means a straight-chained alkoxy group having 1-6 carbon atoms or a branched or cyclic alkoxy group having 3-8 carbon atoms; examples include a methoxy group, an ethoxy group, a n-propoxy group, a n-butoxy group, a n-pentoxy group, a n-hexoxy group, an i-propoxy group, an i-butoxy group, a sec-butoxy group, a tert-butoxy group, an i-pentoxy group, a neopentoxy group, a tert-pentoxy group, an i-hexoxy group, a cyclopropoxy group, a cyclobutoxy group, a cyclopentoxy group, a cyclohexoxy group, a cycloheptoxy group and a cyclooctoxy group.
the lower alkoxycarbonyl group means an alkoxycarbonyl group whose alkyl portion is a straight-chained alkyl group having 1-6 carbon atoms or an alkoxycarbonyl group whose alkyl portion is a branched or cyclic alkyl group having 3-8 carbon atoms, and examples include a methoxycarbonyl group, an ethoxycarbonyl group, a n-propoxycarbonyl group, a n-butoxycarbonyl group, a n-pentoxycarbonyl group, a n-hexoxycarbonyl group, an i-propoxycarbonyl group, an i-butoxycarbonyl group, a sec-butoxycarbonyl group, a tert-butoxycarbonyl group, an i-pentoxycarbonyl group, a neopentoxycarbonyl group, a tert-pentoxycarbonyl group, an i-hexoxycarbonyl group, a cyclopropoxycarbonyl group, a cyclobutoxycarbonyl group, a cyclopentoxycarbonyl group, a cyclohexoxycarbonyl group, a cycloheptoxycarbonyl group and a cyclooctoxycarbonyl group;
the lower alkylsulfonyl group means an alkylsulfonyl group having 1-8 carbon atoms whose alkyl portion is a straight-chained alkyl group or an alkylsulfonyl group having 3-8 carbon atoms whose alkyl portion is a branched or cyclic alkyl group, and examples include a methylsulfonyl group, an ethylsulfonyl group, a propylsulfonyl group, an isopropylsulfonyl group, a butylsulfonyl group and an isobutylsulfonyl group.
the arylsulfonyl group means an aromatic sulfonyl group and examples include a phenylsulfonyl group, a p-tolylsulfonyl group, a p-chlorophenylsulfonyl group, a 2-furylsulfonyl group, a 3-furylsulfonyl group, a 2-thienylsulfonyl group, a 3-thienylsulfonyl group, a 2-pyridylsulfonyl group, a 3-pyridylsulfonyl group and a 4-pyridylsulfonyl group.
Ya and Yb in NYaYb which may be the same or different each represent a hydrogen atom, an optionally substituted lower alkyl group, an optionally substituted lower alkoxycarbonyl group, an acyl group, an optionally substituted lower alkylsulfonyl group or an optionally substituted arylsulfonyl group or, when taken together with the nitrogen atom to which they are bound, may form a 3- to 8-membered ring. The acyl group as used herein means a formyl group or an alkylcarbonyl group having 1-8 carbon atoms whose alkyl portion is an optionally substituted straight-chained alkyl group, an alkylcarbonyl group having 3-8 carbon atoms whose alkyl portion is an optionally substituted branched or cyclic alkyl group, or an arylcarbonyl group, and examples include a formyl group, an acetyl group, a trifluoroacetyl group, a propionyl group, a butyryl group, a valeryl group, an isobutyryl group, an isovaleryl group, a pivaloyl group, a benzoyl group, a phthaloyl group and a toluoyl group.
If R1, R2, R3 R4, R5, R6, R7 or R8 represents an optionally substituted lower alkyl group, an optionally substituted lower alkoxy group, an optionally substituted lower alkoxycarbonyl group or an optionally substituted lower alkylsulfonyl group, the optionally present substituent may be exemplified by a halogen atom, a phenyl group, a hydroxy group, a nitro group, a cyano group, a cyclic alkyl group having 3-8 carbon atoms, a lower alkoxy group optionally substituted by a halogen atom or a phenyl group, a lower alkoxycarbonyl group, a carboxyl group and NYcYd; Yc and Yd which may be the same or different each represent a hydrogen atom, a lower alkyl group, a lower alkoxycarbonyl group, an acyl group, a lower alkylsulfonyl group or an optionally substituted arylsulfonyl group or, when taken together with the nitrogen atom to which they are bonded, may form a 3- to 8-numbered ring.
In the case where R1, R2, R3, R4, R5, R6, R7 or R8 represents a lower alkyl having a halogen atom as a substituent, an xcex1-haloalkyl group may be mentioned as an example. The xcex1-haloalkyl group means a straight-chained alkyl group having 1-6 carbon atoms or a branched or cyclic alkyl group having 3-8 carbon atoms that have 1-3 halogen atoms in 1-position and which may further possess a substituent, and examples include a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a 1-fluoroethyl group, a 1,1-difluoroethyl group, a 1-fluoropropyl group, a 1,1-difluoropropyl group, a 1-fluorocyclopropyl group, a 1-difluorobutyl group, a 1,1-difluorobutyl group, a chloromethyl group, a dichloromethyl group, a trichloromethyl group, a 1-chloroethyl group, a 1,1-dichloroethyl group, a 1-chloropropyl group, a 1,1-chloropropyl group, a 1-chlorocyc lopropyl group, a 1-chlorobutyl group, a 1,1-dichlorobutyl group, a bromomethyl group, a dibromomethyl group, a tribromomethyl group, a 1-bromoethyl group, a 1,1-dibromoethyl group, a 1-bromopropyl group, a 1,1-dibromopropyl group, aa 1-bromocyclopropyl group, a 1-brrmobutyl group, a 1,1-dibromobutyl group, an iodomethyl group, a diodomethyl group, a trurodomethyl group, a 1-modoethyl group, a 1,1-dirodoethyl group, a 1-iodopropyl group, a 1,1-diuodopropyl group, a 1-iodocyclopropyl group, a 1-iodobutyl group and a 1,1-diiodobutyl group.
If R1, R2, R5, R6 or R7 represents an optionally substituted arylsulfonyl group or an optionally substituted aryl group, the optionally present substituent may be exemplified by a halogen atom, a phenyl group, a hydroxy group, a nitro group, a cyano group, a straight-chained alkyl group having 1-6 carbon atoms, a branched or cyclic alkyl group having 3-8 carbon atoms, a lower alkoxy group optionally substituted by a halogen atom or a phenyl group, a lower alkylthio group optionally substituted by a halogen atom or a phenyl group, a lower alkoxycarbonyl group, a carboxyl group and NYeYf; Ye and Yf which may be the same or different each represent a hydrogen atom, an optionally substituted lower alkyl group, an optionally substituted lower alkoxycarbonyl group, an acyl group, an optionally substituted lower alkylsulfonyl group or an arylsulfonyl group or, when taken together, may form a 3- to 8-numbered ring.
Examples of the optionally substituted lower alkyl group as R1 and R2 include a methyl group, a fluoromethyl group, a trifluoromethyl group, a pentafluoroethyl group, a benzyl group, a nitromethyl group, a cyclopropylmethyl group, a methoxymethyl group, an ethoxymethyl group, a benzyloxymethyl group, a methylthiomethyl group, an ethylthiomethyl group, a methoxycarbonylmethyl group, a dimethylaminomethyl group, an ethyl group, a 2-fluoroethyl group, a n-propyl group, an i-propyl group, a 1-methylthiopropyl group and a n-butyl group.
Examples of the optionally substituted lower alkyl group as R3 and R4 include a methyl group, an ethyl group, a n-propyl group, a n-butyl group, a fluoromethyl group, a trifluoromethyl group, a benzyl group, a cyclopropylmethyl group, a 1-fluoroethyl group and a 1,1-difluoroethyl group.
Examples of the optionally substituted lower alkyl group as R5 and R6 include a methyl group, a benzyl group, a cyclopropylmethyl group, an ethyl group, a 2-cyanoethyl group, a 2-fluoroethyl group and a n-propyl group.
Examples of the optionally substituted lower alkoxy group as R1 and R2 include a methoxy group, a trifluoromethoxy group, a benzyloxy group, a cyclopropylmethoxy group, an ethoxy group and a n-propoxy group.
Examples of the optionally substituted lower alkoxycarbonyl group as R1 and R2 include a methoxycarbonyl group, a trifluoromethoxycarbonyl group, a benzyloxycarbonyl group, a cyclopropylmethoxycarbonyl group, an ethoxycarbonyl group, a n-propoxycarbonyl group and a tert-butoxycarbonyl group.
Examples of the above-mentioned NYaYb, NYcYd and NYeYf include an amino group, a methylamino group, a benzylamino group, an ethylamiono group, a dimethylamino group, an ethylmethylamino group, a pyrrolidinyl group, a piperidino group, a morpholino group, an acetamido group, a benzamido group, an N-methylacetamido group, a tert-butoxycarbonylamino group, an N-methyl-tert-butoxycarbonylamino group, a methylsulfonylamino group, an ethylsulfonylamino group, a propylsulfonylamino group, an isopropylsulfonylamino group, a butylsulfonylamino group, an isobutylsulfonylamino group, a phenylsulfonylamino group, a p-tolylsulfonylamino group and a p-chlorophenylsulfonylamino group.
When taken together with the nitrogen atom to which they are bound, Ya and Yb, Yc and Yd, or Ye and Yf may form a 3- to 8-membered ring and the ring has 2-7 carbon atoms, with any carbon atom on the ring being optionally replaced by a nitrogen atom, an oxygen atom or a sulfur atom. Specific examples include an aziridine ring, an azetidine ring, a pyrrole ring, a pyrrolidine ring, a pyridine ring, a 3,4-dihydro-2H-azepine ring, a 3,4,5,6-tetrahydro-2H-azepine ring, an azocine ring, a 5,6-dihydro-azocine ring, a 5,6,7,8-tetrahydroazocine ring, an oxazoline ring, an isoxazoline ring, a thioxazoline ring, a piperazine ring, a morpholine ring and a thiomorpholine ring.
The preferred position of substitution by R1 is in 6-position on the benzopyran ring.
Preferred examples of R1 include an optionally substituted lower alkyl group, an optionally substituted alkylsulfonyl group, an optionally substituted arylsulfonyl group, a nitro group and a cyano group; among these, lower alkyl groups having a fluorine atom as a substituent are preferred, with a 6-trifluoromethyl group and a 6-pentafluoroethyl group being particularly preferred.
The preferred example of R2 is a hydrogen atom.
Speaking of R3 and R4, they are preferably the same; more preferably, they both are an optionally substituted xcex1-haloalkyl group; most preferably, they both are a fluoromethyl group.
Examples of the optionally substituted lower alkyl group as R5 and R6 include a methyl group, a benzyl group, a cyclopropylmethyl group, an ethyl group, a 2-cyanoethyl group, a 2-fluoroethyl group and a n-propyl group.
Speaking of R5 and R6, a preferred case is where R5 is a hydrogen atom and R6 is an optionally substituted lower alkyl group; a more preferred case is where R5 is a hydrogen atom and R6 is a lower alkyl group optionally having a cyano group, and a particularly preferred case is where R5 is a hydrogen atom and R6 is a 2-cyanoethyl group or a 2-cyanomethyl group.
Examples of the optionally substituted alkyl group as R7 include a methyl group, an ethyl group and a propyl group. Examples of the optionally substituted aryl group as R7 include a phenyl group, a p-tolyl group and a p-chlorophenyl group; among these, a p-tolyl group and a methyl group are preferred, with a p-tolyl group being particularly preferred.
Speaking of R8, it represents an optionally substituted lower alkyl group; it is preferably an unsubstituted alkyl group, with a methyl group and an ethyl group being particularly preferred.
The compound of the general formula (I) (where R1, R2, R3, R4 and Hal have the same meanings as defined above) may be synthesized by the following procedure. Stated specifically, the compound can be obtained by heating a compound of the general formula (D-II) (where R1, R2, R3, R4 and Hal have the same meanings as defined above) either with or without a solvent, preferably in a suitable solvent for smooth progress of the reaction, at a temperature between 130xc2x0 C. and the boiling point of the solvent, preferably at 150-200xc2x0 C. The suitable solvent to be used in the reaction is an inert high-boiling point solvent that does not affect the reaction and examples are solvent naphtha, xylene, o-xylene, m-xylene, p-xylene, mesitylene, o-chlorotoluene, m-chlorotoluene, p-chlorotoluene, o-dichlorobenzene, dodecane, tetralin, decalin and diphenyl ether, with solvent naphtha and o-xylene being preferred.
A compound of the general formula (G-VI) (where R1, R2, R3, R4, R5 and R6 have the same meanings as defined above) can typically be synthesized by conversion from the compound of the general formula (I) by a method that involves a carbon monoxide inserting cross-coupling reaction as a key reaction that uses a metal as a catalyst. To be specific, the compound of the general formula (I) (where R1, R2, R3, R4 and Hal have the same meanings as defined above) is subjected to a cross-coupling reaction with a compound of the general formula (G-III)
HNR5R6xe2x80x83xe2x80x83(G-III)
(where R5 and R6 have the same meanings as defined above) in a carbon monoxide stream at atmospheric or subatmospheric pressure from a CO2 gas container, preferably at atmospheric pressure, at a reaction temperature between xe2x88x9278xc2x0 C. and 150xc2x0 C., preferably between room temperature and 130xc2x0 C., for a reaction time of from 1 hour to 3 days, preferably from 3 hours to 1 day, in the presence of a zero-valence or divalent metal catalyst such as palladium, nickel, copper, zinc, tin or magnesium, preferably, 1-5 mol % of zero-valence or divalent palladium such as bis(triphenylphosphine)palladium:acetate, palladium acetate and triphenylphosphine, bis(triphenylphosphine)palladium chloride, [1,1xe2x80x2-bis(diphenylphosphino)ferrocene]palladium chloride dichloromethane adduct, tetrakis(triphenylphosphine)palladium, tris(dibenzylideneacetone)dipalladium chloroform adduct and triphenylphosphine, or tris(dibenzylideneacetone)dipalladium chloroform adduct in a solvent such as N,N-dimethylformamide, tetrahydrofuran, dioxane, ether, acetonitrile, toluene, benzene or water, preferably N,N-dimethylformamide, thereby giving a 4-substituted benzopyran derivative represented by the general formula (G-VI) (where R1, R2, R3, R4, R5 and R6 have the same meanings as defined above).
For synthesis of the compound represented by the general formula (I), the compound represented by the general formula (D-II) is used as an intermediate and this compound, being undocumented and novel, constitutes the present invention. To give the compound of the general formula (D-II), a compound represented by the general formula (C-VI) (where R1, R2, R3 and R4 have the same meanings as defined above) is reacted with a suitable base in a suitable solvent at a temperature between xe2x88x9278xc2x0 C. and the boiling point of the reaction mixture, preferably between xe2x88x9240xc2x0 C. and room temperature, and without subsequent isolation, reaction is performed with a halogen (preferably bromine). The suitable solvent to be used in this reaction is an inert solvent that does not affect the reaction and may be exemplified by hexane, toluene, diethyl ether, diisopropyl ether, tert-butyl methyl ether, tetrahydrofuran and dioxane, with tetrahydrofuran and diethyl ether being preferred. The suitable base tobe used in this reaction is exemplified by alkyllithium such as methyllithium, ethyllithium, n-propyllithium, i-propyllithium, n-butyllithium, sec-butyllithium or tert-butyllithium, alkoxides such as potassium t-butoxide, sodium methoxide and sodium ethoxide, or Grignard reagents such as methylmagnesium chloride, methylmagnesium bromide, methylmagnesium iodide, ethylmagnesium chloride, ethylmagnesium bromide, ethylmagnesium iodide, n-propylmagnesium chloride, n-propylmagnesium bromide, n-propylmagnesium iodide, i-propylmagnesium chloride, i-propylmagnesium bromide, i-propylmagnesium iodide, n-butylmagnesium chloride, n-butylmagnesium bromide, n-butylmagnesium iodide, sec-butylmagnesium chloride, sec-butylmagnesium bromide, sec-butylmagnesium iodide, tert-butylmagnesium chloride, tert-butylmagnesium bromide and tert-butylmagnesium iodide; among these, n-butyllithium and ethylmagnesium bromide are preferred.
The compound of the general formula (D-II) can also be obtained by reacting a compound of the general formula (C-VI) (where R1, R2, R3 and R4 have the same meanings as defined above) with a halogen (preferably bromine) in a suitable solvent in the presence of a suitable base at a temperature between xe2x88x9240xc2x0 C. and room temperature, preferably between 0xc2x0 C. and room temperature. The suitable solvent to be used in this invention may be selected from among alcohols such as methanol, ethanol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, i-butyl alcohol, sec-butyl alcohol and tert-butyl alcohol, mixtures of these alcohols with inert solvents that do not affect the reaction such as diethyl ether, diisopropyl ether, tert-butyl methyl ether, tetrahydrofuran and dioxane; among these, a mixture of tert-butyl methyl ether and tert-butyl alcohol is a preferred solvent system. The suitable base to be used in this reaction is an alkoxide such as potassium tert-butoxide, sodium methoxide or sodium ethoxide, with potassium tert-butoxide being preferred.
For synthesis of the compound represented by the general formula (D-II), the compound represented by the general formula (C-VI) is used as an intermediate and this compound, being undocumented and novel, constituents the present invention. To give the compound of the general formula (C-VI), a sulfonate ester represented by the general formula (C-IV) (where R7, R3 and R4 have the same meanings as defined above) may be reacted with a phenol represented by the general formula (C-V) (where R1 and R2 have the same meanings as definedabove) in an inert solvent such as acetonitrile that does not affect the reaction, in the presence of a suitable base and a catalytic amount of a suitable copper salt at a temperature between xe2x88x9278xc2x0 C. and room temperature, preferably between 0xc2x0 C. and room temperature. Examples of the suitable base that can be used in the reaction include organic strong bases such as 1,8-diazabicyclo(5.4.0)-7-undecene and 1,5-diazabicyclo(4.3.0)-5-nonene, and tertiary amines such as triethylamine, tributylamine and N,N-diisopropylethylamine, with N,N-diisopropylethylamine being preferred. Exampples of the suitable copper salt that can be used in the reaction include cuprous salts such as copper(I) acetate, copper(I) trifluoroacetate, cuprous chloride, cuprous bromide, cuprous iodide and cuprous cyanide, and cupric salts such as cupric chloride and cupric bromide, with cupric chloride and cupric bromide being preferred.
For synthesis of the compound of the general formula (C-VI), the compound represented by the general formula (C-IV) is used as an intermediate and this compound, being undocumented and novel, constitutes the present invention. To prepare the compound of the general formula (C-IV), an alcohol represented by the general formula (C-I) (where R3 and R4 have the same meanings as defined above) may be reacted with a compound of the general formula (C-II) or (C-III)
R7SO2Clxe2x80x83xe2x80x83(C-II)
(R7SO2)2Oxe2x80x83xe2x80x83(C-III)
(where R7 represents an optionally substituted alkyl group or an optionally substituted aryl group) either after reacting the alcohol with a suitable base in a suitable solvent to be converted to an alkoxide or directly in a suitable solvent in the presence of a suitable base at a temperature between xe2x88x9278xc2x0 C. and room temperature, preferably between 0xc2x0 C. and room temperature. In this reaction, a suitable catalyst such as N,N-dimethylaminopyridine may be used. The suitable solvent that can be used in this reaction is an inert solvent that does not affect the reaction, as exemplified by diethyl ether, diisopropyl ether, tert-butyl methyl ether, tetrahydrofuran, dioxane, diglyme, acetone, N,N-dimethylformamide, N,N-dimethylacetamide and dimethyl sulfide, with tetrahydrofuran and tert-butyl methyl ether being preferred. Examples of the suitable base that can be used in the reaction include alkali metal hydrides such as potassium hydride, sodium hydride and lithium hydride, or carbonates such as potassium carbonate and sodium carbonate, bicarbonates such as potassium hydrogencarbonate and sodium hydrogencarbonate, organic strong bases such as 1,87diazabicyclo(5.4.0)-7-undecene and 1,5-diazabicyclo(4.3.0)-5-nonene, tertiary amines such as triethylamine, tributylamine and N,N-diisopropylethylamine; among these, sodium hydride and triethylamine are preferred.
Among the compounds represented by the general formula (H-V), a compound in which R3 and R4 are a trifluoromethyl group (xe2x80x94CH2F) is an undocumented novel compound and constitutes the present invention. To give the compound of the general formula (H-V), a compound represented by the general formula (H-IV) (where R1, R2, R3, R4 and R8 have the same meanings as defined above) may be rapidly heated to a temperature between 180xc2x0 C. and 250xc2x0 C., preferably between 180xc2x0 C. and 200xc2x0 C., either with or without a solvent, preferably in a suitable solvent for smooth progress of the reaction, either at atmospheric or superatmospheric pressure. The suitable solvent to be used in this reaction is a high-boiling point solvent that does not affect the reaction and may be exemplified by mesitylene, dichlorobenzene, dodecane, tetralin, decalin and diphenyl ether, with 1,2-dichlorobenzene being preferred.
For synthesis of the compound represented by the general formula (H-V), the compound represented by the general formula (H-IV) is used as an intermediate. Among the compounds represented by the general formula (H-IV), a compound in which R3 and R4 are a trifluoromethyl group (xe2x80x94CH2F) is an undocumented novel compound and constitutes the present invention. To give the compound of the general formula (H-IV), a compound represented by the general formula (C-VI) (where R1, R2, R3 and R4 have the same meanings as defined above) is reacted with a suitable base in a suitable solvent at a temperature between xe2x88x9278xc2x0 C. and the boiling point of the reaction mixture, preferably between xe2x88x9240xc2x0 C. and room temperature, and without subsequent isolation, reaction is performed with a compound represented by the general formula (H-II)
xe2x80x83OC(OR8)2xe2x80x83xe2x80x83(H-II)
or the general formula (H-III)
ClC(O)R8xe2x80x83xe2x80x83(H-III)
(where R8 represents an optionally substituted lower alkyl group). The suitable solvent to be used in this reaction is an inert solvent that does not affect the reaction and may be exemplified by hexane, toluene, diethyl ether, diisopropyl ether, tert-butyl methyl ether, tetrahydrofuran and dioxane, with tetrahydrofuran and diethyl ether being preferred. The suitable base to be used in this reaction is exemplified by alkyllithium such as methyllithium, ethyllithium, n-propyllithium, i-propyllithium, n-butyllithium, sec-butyllithium or tert-butyllithium, or Grignard reagents such as methylmagnesium chloride, methylmagnesium bromide, methylmagnesium iodide, ethylmagnesium chloride, ethylmagnesium bromide, ethylmagnesium iodide, n-propylmagnesium chloride, n-propylmagnesium bromide, n-propylmagnesium iodide, i-propylmagnesium chloride, i-propylmagnesium bromide, i-propylmagnesium iodide, n-butylmagnesium chloride, n-butylmagnesium bromide, n-butylmagnesium iodide, sec-butylmagnesium chloride, sec-butylmagnesium bromide, sec-butylmagnesium iodide, tert-butylmagnesium chloride, tert-butylmagnesium bromide and tert-butylmagnesium iodide, and alkoxides such as potassium t-butoxide, sodium methoxide and sodium ethoxide; among these, n-butyllithium and ethylmagnesium bromide are preferred.
The compound represented by.the general formula (G-VI) can be obtained by conversion from the compound of the general formula (H-V) in the following manner. To be specific, the compound represented by the general formula (H-V) (where R1, R2, R3, R4 and R8 have the same meanings as defined above) is reacted with a suitable reagent in a suitable solvent at a temperature between 0xc2x0 C. and the boiling point of the solvent, preferably between room temperature and 80xc2x0 C., to effect hydrolysis (conversion from xe2x80x94COOR8 to xe2x80x94COOH); thereafter, the carboxylate is reacted with a compound represented by the general formula (G-III)
HNR5R6xe2x80x83xe2x80x83(G-III)
(where R5 and R6 have the same meanings as defined above) and a suitable reagent to effect dehydrative condensation in a suitable solvent at a temperature between 0xc2x0 C. and the boiling point of the solvent, preferably at room temperature, thereby producing the general formula (G-VI) (where R1, R2, R3, R4, R5 and R6 have the same meanings as defined above).
The suitable solvent for use in hydrolysis is an inert solvent that does not affect the reaction, as exemplified by water, methanol, ethanol, isopropanol, hydrous methanol, hydrous ethanol, hydrous isopropanol, hydrous tetrahydrofuran, hydrous dioxane, benzene and toluene, with ethanol being preferred. The suitable reagent for use in hydrolysis is a base such as lithium hydroxide, sodium hydroxide, potassium hydroxide, barium hydroxide, lithium carbonate, sodium carbonate or potassium carbonate, or an acid such as hydrochloric acid, hydrobromic acid, acetic acid or sulfuric acid, with potassium hydroxide being preferred.
The suitable solvent for use in dehydrative condensation is an inert solvent that does not affect the reaction, as exemplified by tetrahydrofuran, dichloromethane, chloroform, carbon tetrachloride, acetonitrile, benzene, toluene, N,N-dimethylformamide and dimethyl sulfoxide, with tetrahydrofuran being preferred. The suitable reagent for use in dehydrative condensation may be selected from among reagents such as N,Nxe2x80x2-carbonyldiimidazole, 1,3-dicyclohexylcarbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, 2,2xe2x80x2-pyridine sulfide and triphenylphosphine, 2-ethoxy-1-ethoxycarbonyl-1,2-dihydroquinoline, thionyl chloride, phosphorus pentochloride and phosphorus oxychloride; among these, N,Nxe2x80x2-carbonyldiimidazole is preferred.